Multiple checkers slow hashing on local HDDs

[Drexel]

What is the problem you are having with rclone?

I am using rclone with data on a local HDD. I came in a situation where rclone started hashing local files and it took very long. I tried to optimize it with reducing checkers and delaying transfers with --check-first. Reducing --checkers to 1 speeded up the hashing but slowed down the modtime checking, --checkers 2 speeded up the modtime checking but slowed down the hashing again.

Run the command 'rclone version' and share the full output of the command.

rclone v1.75.1

• os/version: Microsoft Windows 11 Pro 26H2 26H2 (64 bit)
• os/kernel: 10.0.26300.9457 (x86_64)
• os/type: windows
• os/arch: amd64
• go/version: go1.26.8
• go/linking: static
• go/tags: cmount

Which cloud storage system are you using? (eg Google Drive)

I clone from local to SMB or local to local (USB HDD)

The command you were trying to run (eg rclone copy /tmp remote:tmp)

rclone sync e:\path\to\folder v:\path\to\remote -v --create-empty-src-dirs --progress --log-file e:\path\to\logfile --check-first --checkers 2 --transfers 2

Please run 'rclone config redacted' and share the full output. If you get command not found, please make sure to update rclone.

; empty config

A log from the command that you were trying to run with the -vv flag

One log with 2 checkers (1m21.0s), the same with 1 checker takes 34.5s.

2026/10/05 11:24:44 DEBUG : rclone: Version "v1.75.1" starting with parameters ["rclone" "sync" "d:\\rctest" "v:\\rctest" "-vv" "--create-empty-src-dirs" "--progress" "--log-file" "d:\\log.txt" "--check-first" "--checkers" "2" "--transfers" "2"]
2026/10/05 11:24:44 DEBUG : Creating backend with remote "d:\\rctest"
2026/10/05 11:24:44 DEBUG : Using config file from "C:\\Users\\Matthias\\AppData\\Roaming\\rclone\\rclone.conf"
2026/10/05 11:24:44 DEBUG : fs cache: renaming cache item "d:\\rctest" to be canonical "//?/d:/rctest"
2026/10/05 11:24:44 DEBUG : Creating backend with remote "v:\\rctest"
2026/10/05 11:24:44 DEBUG : fs cache: renaming cache item "v:\\rctest" to be canonical "//?/v:/rctest"
2026/10/05 11:24:44 INFO  : Local file system at //?/v:/rctest: Running all checks before starting transfers
2026/10/05 11:24:44 DEBUG : 0302.bin: size = 1619842 OK
2026/10/05 11:24:44 INFO  : 0307: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0307", newDst=0307
2026/10/05 11:24:44 DEBUG : 0303.bin: size = 2643 OK
2026/10/05 11:24:44 DEBUG : 0302.bin: Modification times differ by 871.5616ms: 2003-10-08 00:02:17.1284384 +0200 CEST, 2003-10-08 00:02:18 +0200 CEST
2026/10/05 11:24:44 INFO  : 0308: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308", newDst=0308
2026/10/05 11:24:44 DEBUG : 0303.bin: Modification times differ by 1.09375s: 2006-08-17 18:43:12.90625 +0200 CEST, 2006-08-17 18:43:14 +0200 CEST
2026/10/05 11:24:44 INFO  : 0308/0288: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308/0288", newDst=0308/0288
2026/10/05 11:24:44 INFO  : 0308/0288/0270: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308/0288/0270", newDst=0308/0288/0270
2026/10/05 11:24:44 INFO  : 0308/0288/0274: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308/0288/0274", newDst=0308/0288/0274
2026/10/05 11:24:44 INFO  : 0308/0288/0275: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308/0288/0275", newDst=0308/0288/0275
2026/10/05 11:24:44 INFO  : 0308/0288/0276: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308/0288/0276", newDst=0308/0288/0276
2026/10/05 11:24:44 INFO  : 0308/0288/0274/0222: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308/0288/0274/0222", newDst=0308/0288/0274/0222
2026/10/05 11:24:44 INFO  : 0308/0288/0274/0223: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308/0288/0274/0223", newDst=0308/0288/0274/0223
2026/10/05 11:24:44 INFO  : 0308/0288/0274/0244: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308/0288/0274/0244", newDst=0308/0288/0274/0244
2026/10/05 11:24:44 INFO  : 0308/0288/0274/0246: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308/0288/0274/0246", newDst=0308/0288/0274/0246
2026/10/05 11:24:44 INFO  : 0308/0288/0274/0252: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308/0288/0274/0252", newDst=0308/0288/0274/0252
2026/10/05 11:24:44 INFO  : 0308/0288/0274/0256: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308/0288/0274/0256", newDst=0308/0288/0274/0256
2026/10/05 11:24:44 INFO  : 0308/0288/0274/0257: Set directory modification time (using SetModTime)
2026/10/05 11:24:44 DEBUG : Added delayed dir = "0308/0288/0274/0257", newDst=0308/0288/0274/0257
2026/10/05 11:24:44 DEBUG : Local file system at //?/v:/rctest: Waiting for checks to finish
2026/10/05 11:24:44 DEBUG : 0303.bin: md5 = 0a11a90179e561bd00bbaa505ba7cc39 OK
2026/10/05 11:24:44 INFO  : 0303.bin: Updated modification time in destination
2026/10/05 11:24:44 DEBUG : 0303.bin: Unchanged skipping
2026/10/05 11:24:44 DEBUG : 0304.bin: size = 800678424 OK
2026/10/05 11:24:44 DEBUG : 0304.bin: Modification times differ by 1s: 2007-10-10 08:12:55 +0200 CEST, 2007-10-10 08:12:56 +0200 CEST
2026/10/05 11:24:44 DEBUG : 0302.bin: md5 = eb9cd45a1fa7fc3063e58c1635a3f8a8 OK
2026/10/05 11:24:44 INFO  : 0302.bin: Updated modification time in destination
2026/10/05 11:24:44 DEBUG : 0302.bin: Unchanged skipping
2026/10/05 11:24:44 DEBUG : 0305.bin: size = 29 OK
2026/10/05 11:24:44 DEBUG : 0305.bin: Modification times differ by 1.21875s: 2007-08-04 11:09:42.78125 +0200 CEST, 2007-08-04 11:09:44 +0200 CEST
2026/10/05 11:24:44 DEBUG : 0305.bin: md5 = 38123e177638ded6916f040ebe6ab895 OK
2026/10/05 11:24:44 INFO  : 0305.bin: Updated modification time in destination
2026/10/05 11:24:44 DEBUG : 0305.bin: Unchanged skipping
2026/10/05 11:24:44 DEBUG : 0306.bin: size = 619771904 OK
2026/10/05 11:24:44 DEBUG : 0306.bin: Modification times differ by 1.211976s: 2009-01-23 22:31:36.788024 +0100 CET, 2009-01-23 22:31:38 +0100 CET
2026/10/05 11:25:05 DEBUG : 0306.bin: md5 = c5e0a206f644263e9201b9d041d0c132 OK
2026/10/05 11:25:05 INFO  : 0306.bin: Updated modification time in destination
2026/10/05 11:25:05 DEBUG : 0306.bin: Unchanged skipping
2026/10/05 11:25:05 DEBUG : 0307/0287.bin: size = 645 OK
2026/10/05 11:25:05 DEBUG : 0307/0287.bin: Modification times differ by 1.678148s: 2011-09-25 14:10:16.321852 +0200 CEST, 2011-09-25 14:10:18 +0200 CEST
2026/10/05 11:25:05 DEBUG : 0307/0287.bin: md5 = 0c05de848fffd24476458864066c1064 OK
2026/10/05 11:25:05 INFO  : 0307/0287.bin: Updated modification time in destination
2026/10/05 11:25:05 DEBUG : 0307/0287.bin: Unchanged skipping
2026/10/05 11:25:05 DEBUG : 0307/0290.bin: size = 699842560 OK
2026/10/05 11:25:05 DEBUG : 0307/0290.bin: Modification times differ by 823.673ms: 2011-09-25 16:43:39.176327 +0200 CEST, 2011-09-25 16:43:40 +0200 CEST
2026/10/05 11:25:12 DEBUG : 0304.bin: md5 = 4bdfbb089446f00ba35357468d43d8fe OK
2026/10/05 11:25:12 INFO  : 0304.bin: Updated modification time in destination
2026/10/05 11:25:12 DEBUG : 0304.bin: Unchanged skipping
2026/10/05 11:25:12 DEBUG : 0307/0291.bin: size = 33 OK
2026/10/05 11:25:12 DEBUG : 0307/0291.bin: Modification times differ by 1.674148s: 2011-09-25 14:10:16.325852 +0200 CEST, 2011-09-25 14:10:18 +0200 CEST
2026/10/05 11:25:12 DEBUG : 0307/0291.bin: md5 = 892830990fba4934d2ee5c7f10d59adc OK
2026/10/05 11:25:12 INFO  : 0307/0291.bin: Updated modification time in destination
2026/10/05 11:25:12 DEBUG : 0307/0291.bin: Unchanged skipping
2026/10/05 11:25:12 DEBUG : 0307/0292.bin: size = 698486784 OK
2026/10/05 11:25:12 DEBUG : 0307/0292.bin: Modification times differ by 1.806474s: 2011-09-25 16:43:38.193526 +0200 CEST, 2011-09-25 16:43:40 +0200 CEST
2026/10/05 11:25:27 DEBUG : 0307/0290.bin: md5 = b878fffbd696f4ceb4c2a7db368cd066 OK
2026/10/05 11:25:27 INFO  : 0307/0290.bin: Updated modification time in destination
2026/10/05 11:25:27 DEBUG : 0307/0290.bin: Unchanged skipping
2026/10/05 11:25:27 DEBUG : 0307/0297.bin: size = 698486784 OK
2026/10/05 11:25:27 DEBUG : 0307/0297.bin: Modification times differ by 1.806474s: 2011-09-25 16:43:38.193526 +0200 CEST, 2011-09-25 16:43:40 +0200 CEST
2026/10/05 11:25:32 DEBUG : 0307/0292.bin: md5 = 0d87d4686550bbd450ecebca224057f7 OK
2026/10/05 11:25:32 INFO  : 0307/0292.bin: Updated modification time in destination
2026/10/05 11:25:32 DEBUG : 0307/0292.bin: Unchanged skipping
2026/10/05 11:25:32 DEBUG : 0307/0298.bin: size = 699842560 OK
2026/10/05 11:25:32 DEBUG : 0307/0298.bin: Modification times differ by 823.673ms: 2011-09-25 16:43:39.176327 +0200 CEST, 2011-09-25 16:43:40 +0200 CEST
2026/10/05 11:25:51 DEBUG : 0307/0297.bin: md5 = 0d87d4686550bbd450ecebca224057f7 OK
2026/10/05 11:25:51 INFO  : 0307/0297.bin: Updated modification time in destination
2026/10/05 11:25:51 DEBUG : 0307/0297.bin: Unchanged skipping
2026/10/05 11:25:51 DEBUG : 0307/0299.bin: size = 645 OK
2026/10/05 11:25:51 DEBUG : 0307/0299.bin: Modification times differ by 1.678148s: 2011-09-25 14:10:16.321852 +0200 CEST, 2011-09-25 14:10:18 +0200 CEST
2026/10/05 11:25:51 DEBUG : 0307/0299.bin: md5 = 0c05de848fffd24476458864066c1064 OK
2026/10/05 11:25:51 INFO  : 0307/0299.bin: Updated modification time in destination
2026/10/05 11:25:51 DEBUG : 0307/0299.bin: Unchanged skipping
2026/10/05 11:25:51 DEBUG : 0307/0300.bin: size = 33 OK
2026/10/05 11:25:51 DEBUG : 0307/0300.bin: Modification times differ by 1.674148s: 2011-09-25 14:10:16.325852 +0200 CEST, 2011-09-25 14:10:18 +0200 CEST
2026/10/05 11:25:51 DEBUG : 0307/0300.bin: md5 = 892830990fba4934d2ee5c7f10d59adc OK
2026/10/05 11:25:51 INFO  : 0307/0300.bin: Updated modification time in destination
2026/10/05 11:25:51 DEBUG : 0307/0300.bin: Unchanged skipping
2026/10/05 11:25:51 DEBUG : 0308/0288/0109.bin: size = 4493155 OK
2026/10/05 11:25:51 DEBUG : 0308/0288/0109.bin: Modification times differ by 1s: 2002-06-14 22:47:05 +0200 CEST, 2002-06-14 22:47:06 +0200 CEST
2026/10/05 11:25:51 DEBUG : 0308/0288/0109.bin: md5 = 6bf5d062d0b1629d3cfdaea28adce019 OK
2026/10/05 11:25:51 INFO  : 0308/0288/0109.bin: Updated modification time in destination
2026/10/05 11:25:51 DEBUG : 0308/0288/0109.bin: Unchanged skipping
2026/10/05 11:25:51 DEBUG : 0308/0288/0260.bin: size = 53248 OK
2026/10/05 11:25:51 DEBUG : 0308/0288/0260.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:51 DEBUG : 0308/0288/0260.bin: Unchanged skipping
2026/10/05 11:25:51 DEBUG : 0308/0288/0261.bin: size = 571 OK
2026/10/05 11:25:51 DEBUG : 0308/0288/0261.bin: Modification times differ by 766.674ms: 2011-10-21 17:42:11.233326 +0200 CEST, 2011-10-21 17:42:12 +0200 CEST
2026/10/05 11:25:51 DEBUG : 0308/0288/0261.bin: md5 = f9063acdc3cc2ecb47454eb960e919d1 OK
2026/10/05 11:25:51 INFO  : 0308/0288/0261.bin: Updated modification time in destination
2026/10/05 11:25:51 DEBUG : 0308/0288/0261.bin: Unchanged skipping
2026/10/05 11:25:51 DEBUG : 0308/0288/0262.bin: size = 299008 OK
2026/10/05 11:25:51 DEBUG : 0308/0288/0262.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:51 DEBUG : 0308/0288/0262.bin: Unchanged skipping
2026/10/05 11:25:51 DEBUG : 0308/0288/0263.bin: size = 47 OK
2026/10/05 11:25:51 DEBUG : 0308/0288/0263.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:51 DEBUG : 0308/0288/0263.bin: Unchanged skipping
2026/10/05 11:25:51 DEBUG : 0308/0288/0265.bin: size = 17710342 OK
2026/10/05 11:25:51 DEBUG : 0308/0288/0265.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:51 DEBUG : 0308/0288/0265.bin: Unchanged skipping
2026/10/05 11:25:51 DEBUG : 0308/0288/0267.bin: size = 21630 OK
2026/10/05 11:25:51 DEBUG : 0308/0288/0267.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:51 DEBUG : 0308/0288/0267.bin: Unchanged skipping
2026/10/05 11:25:51 DEBUG : 0308/0288/0268.bin: size = 422968683 OK
2026/10/05 11:25:51 DEBUG : 0308/0288/0268.bin: Modification times differ by 1s: 2002-06-18 05:27:01 +0200 CEST, 2002-06-18 05:27:02 +0200 CEST
2026/10/05 11:25:58 DEBUG : 0307/0298.bin: md5 = b878fffbd696f4ceb4c2a7db368cd066 OK
2026/10/05 11:25:58 INFO  : 0307/0298.bin: Updated modification time in destination
2026/10/05 11:25:58 DEBUG : 0307/0298.bin: Unchanged skipping
2026/10/05 11:25:58 DEBUG : 0308/0288/0270/0139.bin: size = 11090032 OK
2026/10/05 11:25:58 DEBUG : 0308/0288/0270/0139.bin: Modification times differ by 1s: 2002-06-13 15:14:15 +0200 CEST, 2002-06-13 15:14:16 +0200 CEST
2026/10/05 11:25:58 DEBUG : 0308/0288/0270/0139.bin: md5 = 75cc3f54fba592772d5d33dc6d96f050 OK
2026/10/05 11:25:58 INFO  : 0308/0288/0270/0139.bin: Updated modification time in destination
2026/10/05 11:25:58 DEBUG : 0308/0288/0270/0139.bin: Unchanged skipping
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0161.bin: size = 341264 OK
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0161.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0161.bin: Unchanged skipping
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0162.bin: size = 41984 OK
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0162.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0162.bin: Unchanged skipping
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0165.bin: size = 1901056 OK
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0165.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0165.bin: Unchanged skipping
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0166.bin: size = 47616 OK
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0166.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0166.bin: Unchanged skipping
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0203.bin: size = 14382402 OK
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0203.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0203.bin: Unchanged skipping
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0205.bin: size = 140288 OK
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0205.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0205.bin: Unchanged skipping
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0210.bin: size = 35328 OK
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0210.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0210.bin: Unchanged skipping
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0221.bin: size = 562548 OK
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0221.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0221.bin: Unchanged skipping
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0238.bin: size = 9917535 OK
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0238.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0238.bin: Unchanged skipping
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0247.bin: size = 562193 OK
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0247.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:25:58 DEBUG : 0308/0288/0275/0247.bin: Unchanged skipping
2026/10/05 11:25:58 DEBUG : 0308/0288/0276/0149.bin: size = 16447210 OK
2026/10/05 11:25:58 DEBUG : 0308/0288/0276/0149.bin: Modification times differ by 1s: 2002-06-15 19:15:49 +0200 CEST, 2002-06-15 19:15:50 +0200 CEST
2026/10/05 11:25:59 DEBUG : 0308/0288/0276/0149.bin: md5 = 90c62c625e3e61fac60cf7955f683b72 OK
2026/10/05 11:25:59 INFO  : 0308/0288/0276/0149.bin: Updated modification time in destination
2026/10/05 11:25:59 DEBUG : 0308/0288/0276/0149.bin: Unchanged skipping
2026/10/05 11:25:59 DEBUG : 0308/0288/0276/0151.bin: size = 21283740 OK
2026/10/05 11:25:59 DEBUG : 0308/0288/0276/0151.bin: Modification times differ by 1s: 2002-06-17 15:25:45 +0200 CEST, 2002-06-17 15:25:46 +0200 CEST
2026/10/05 11:26:00 DEBUG : 0308/0288/0276/0151.bin: md5 = 46c2549bd26462afbf98d59d955cb923 OK
2026/10/05 11:26:00 INFO  : 0308/0288/0276/0151.bin: Updated modification time in destination
2026/10/05 11:26:00 DEBUG : 0308/0288/0276/0151.bin: Unchanged skipping
2026/10/05 11:26:00 DEBUG : 0308/0288/0276/0158.bin: size = 19138382 OK
2026/10/05 11:26:00 DEBUG : 0308/0288/0276/0158.bin: Modification times differ by 1s: 2002-06-15 19:15:41 +0200 CEST, 2002-06-15 19:15:42 +0200 CEST
2026/10/05 11:26:01 DEBUG : 0308/0288/0276/0158.bin: md5 = d123190fff3c31cc20771507f0cf758b OK
2026/10/05 11:26:01 INFO  : 0308/0288/0276/0158.bin: Updated modification time in destination
2026/10/05 11:26:01 DEBUG : 0308/0288/0276/0158.bin: Unchanged skipping
2026/10/05 11:26:01 DEBUG : 0308/0288/0276/0206.bin: size = 15052312 OK
2026/10/05 11:26:01 DEBUG : 0308/0288/0276/0206.bin: Modification times differ by 1s: 2002-06-15 19:15:53 +0200 CEST, 2002-06-15 19:15:54 +0200 CEST
2026/10/05 11:26:01 DEBUG : 0308/0288/0276/0206.bin: md5 = 8a1b8090bbae1ba11c3bb56a38fdb90f OK
2026/10/05 11:26:01 INFO  : 0308/0288/0276/0206.bin: Updated modification time in destination
2026/10/05 11:26:01 DEBUG : 0308/0288/0276/0206.bin: Unchanged skipping
2026/10/05 11:26:01 DEBUG : 0308/0288/0276/0214.bin: size = 18910086 OK
2026/10/05 11:26:01 DEBUG : 0308/0288/0276/0214.bin: Modification times differ by 1s: 2002-06-15 19:15:35 +0200 CEST, 2002-06-15 19:15:36 +0200 CEST
2026/10/05 11:26:02 DEBUG : 0308/0288/0276/0214.bin: md5 = 72c756e6f440cbbced73a947b6de6a44 OK
2026/10/05 11:26:02 INFO  : 0308/0288/0276/0214.bin: Updated modification time in destination
2026/10/05 11:26:02 DEBUG : 0308/0288/0276/0214.bin: Unchanged skipping
2026/10/05 11:26:02 DEBUG : 0308/0288/0276/0217.bin: size = 26364362 OK
2026/10/05 11:26:02 DEBUG : 0308/0288/0276/0217.bin: Modification times differ by 1s: 2002-06-15 19:15:39 +0200 CEST, 2002-06-15 19:15:40 +0200 CEST
2026/10/05 11:26:03 DEBUG : 0308/0288/0276/0217.bin: md5 = 812b1468bc268bd69d5bc85c091f4230 OK
2026/10/05 11:26:03 INFO  : 0308/0288/0276/0217.bin: Updated modification time in destination
2026/10/05 11:26:03 DEBUG : 0308/0288/0276/0217.bin: Unchanged skipping
2026/10/05 11:26:03 DEBUG : 0308/0288/0276/0235.bin: size = 28432146 OK
2026/10/05 11:26:03 DEBUG : 0308/0288/0276/0235.bin: Modification times differ by 1s: 2002-06-15 19:15:43 +0200 CEST, 2002-06-15 19:15:44 +0200 CEST
2026/10/05 11:26:04 DEBUG : 0308/0288/0276/0235.bin: md5 = f0fe73cdeb19b8e10a7191dce3eb776d OK
2026/10/05 11:26:04 INFO  : 0308/0288/0276/0235.bin: Updated modification time in destination
2026/10/05 11:26:04 DEBUG : 0308/0288/0276/0235.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0001.bin: size = 11640 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0001.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0001.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0002.bin: size = 16430 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0002.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0002.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0019.bin: size = 3148 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0019.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0019.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0020.bin: size = 3164 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0020.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0020.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0044.bin: size = 18411 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0044.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0223/0044.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0005.bin: size = 6944 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0005.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0005.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0008.bin: size = 6935 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0008.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0008.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0015.bin: size = 2334 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0015.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0015.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0016.bin: size = 6500 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0016.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0016.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0025.bin: size = 14420 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0025.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0025.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0026.bin: size = 6417 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0026.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0026.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0027.bin: size = 417 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0027.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0027.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0029.bin: size = 14921 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0029.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0029.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0030.bin: size = 10580 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0030.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0030.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0031.bin: size = 26648 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0031.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0031.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0048.bin: size = 12539 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0048.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0048.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0067.bin: size = 14323 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0067.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0067.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0072.bin: size = 2151 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0072.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0222/0072.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0003.bin: size = 2569 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0003.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0003.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0004.bin: size = 8336 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0004.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0004.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0006.bin: size = 20484 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0006.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0006.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0007.bin: size = 13654 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0007.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0007.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0013.bin: size = 3886 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0013.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0013.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0018.bin: size = 5320 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0018.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0018.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0033.bin: size = 4769 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0033.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0244/0033.bin: Unchanged skipping

....

2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0256/0130.bin: size = 300 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0256/0130.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0256/0130.bin: Unchanged skipping
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0256/0132.bin: size = 1052 OK
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0256/0132.bin: Size and modification time the same (differ by 0s, within tolerance 100ns)
2026/10/05 11:26:04 DEBUG : 0308/0288/0274/0256/0132.bin: Unchanged skipping
2026/10/05 11:26:05 DEBUG : 0308/0288/0268.bin: md5 = 7e323b6a5e57540dc2e7daa7e242d6a2 OK
2026/10/05 11:26:05 INFO  : 0308/0288/0268.bin: Updated modification time in destination
2026/10/05 11:26:05 DEBUG : 0308/0288/0268.bin: Unchanged skipping
2026/10/05 11:26:05 INFO  : Local file system at //?/v:/rctest: Checks finished, now starting transfers
2026/10/05 11:26:05 DEBUG : Local file system at //?/v:/rctest: Waiting for transfers to finish
2026/10/05 11:26:05 DEBUG : Waiting for deletions to finish
2026/10/05 11:26:05 INFO  : There was nothing to transfer
2026/10/05 11:26:05 INFO  : 
Transferred:   	          0 B / 0 B, -, 0 B/s, ETA -
Checks:               135 / 135, 100%, Listed 298
Elapsed time:      1m21.0s

2026/10/05 11:26:05 DEBUG : 1 go routines active

Maybe there should be a possibilty to pause other checkers when one checker is hashing a file beyond a size threshold?

[asdffdsa (jojothehumanmonkey)]

welcome to the forum,

@Drexel

Maybe there should be a possibilty to pause other checkers when one checker is hashing a file beyond a size threshold?

tl;dr, i think that is a niche feature, would not get implemented.

• in your first command, to prevent the computation of the hashes, could use --modify-window=2s
• perhaps could tweak --order-by

fwiw, i would just let rclone do its thing.

---

if you pick one single file to focus on, might get a better understanding of what rclone is doing.

i think this is what is going on.
keep in mind that rclone is optimized for cloud transfers, not local to local transfers.
transferring a file from local to cloud can be much more expensive then local to local.
in terms of time, internet bandwidth, storage costs, api calls and so on.
rclone really tries to avoid that expensive transfer.

1.	0303.bin: size = 2643 OK
2.  0303.bin: Modification times differ by 1.09375s: 2006-08-17 18:43:12.90625 +0200 CEST, 2006-08-17 18:43:14 +0200 CEST
3.	0303.bin: md5 = 0a11a90179e561bd00bbaa505ba7cc39 OK
4.	0303.bin: Updated modification time in destination
5. 	0303.bin: Unchanged skipping

1. rclone does a quick,cheap compare of size for the for source file and dest file.
   the sizes match. if the size did not match, rclone must do a transfer
2. rclone does a quick,cheap compare of modtime for the for source file and dest file.
   the modtimes do not match

what is rclone do to?
a. be dumb and do the expensive transfer
b. be smart, try to avoid an unnecessary expensive transfer.

3. to be smart, rclone will calculate the hash for the source file and dest.
4. in your case, the source file and dest file are identical, no need to transfer.
   so rclone can do a quick,cheap modtime update.
5. that expensive file transfer is not required.

---

@Drexel

There was nothing to transfer

if you run the exact same command again, what happens.
since rclone has fixed the modtimes, the command should take only a few seconds.

which leads to the question, as to why all the files are identical but the modtimes are offset by a small amount, most by 1s ?

[kapitainsky]

@Drexel

rclone sync e:\path\to\folder v:\path\to\remote

Given that your local HDD speed is bottleneck you won't benefit from rclone parallel operations anyway. Maybe try something else? rsync for example.

In order to help you more maybe you can shed some light why you decided to use rclone in the first place for local operations?

[asdffdsa (jojothehumanmonkey)]

@kapitainsky

Maybe try something else? rsync for example.

hey @kapitainsky, how would rsync help. i thought it was single-threaded?
what flags would you recommend?

---

as for running rsync on windows, it runs great, i first started using it 5+ years ago.

i wrote about it at
i run run rsync on windows dozens of times every day, on small files, i use --whole-file --checksum

and here is more detailed rsync info from my self-written backup software, which runs on both windows and linux.

rsync_flags=--checksum --itemize-changes --times -vv --recursive --whole-file --delete --log-file="!LOGDIRL/rsync.log"
cmd03=rsync --backup  "${source_dir}/" "${dest_dir}/rsync/current"  --backup-dir="${dest_dir}/rsync/archive/!DATETIME"  ${rsync_flags}

[Drexel]

Thank you for all your answers.

@asdffdsa

keep in mind that rclone is optimized for cloud transfers, not local to local transfers.

I am aware, maybe it isn't the right tool for me after all.

@asdffdsa

which leads to the question, as to why all the files are identical but the modtimes are offset by a small amount, most by 1s ?

I think because my external storage is exFat file system, while the source is NTFS and they have different modtime precision.

@asdffdsa

if you run the exact same command again, what happens.

The same.

@kapitainsky

Given that your local HDD speed is bottleneck you won't benefit from rclone parallel operations anyway. Maybe try something else? rsync for example.

In order to help you more maybe you can shed some light why you decided to use rclone in the first place for local operations?

I am under Windows, rsync is not really an option without the Linux subsystem, which I don't want to install for one command. I came from FreeFileSync, which I don't want to use anymore because of the license mess and development model. It tried rclone, Unison and robocopy. rclone looked nice first also for local backup, but currently I am with robocopy. It does what I want, but I don't like that you can't differntiate between console output and log output. Either you have no progress information on console or a lot of progress lines per file in the log...

[asdffdsa (jojothehumanmonkey)]

@Drexel

I am under Windows, rsync is not really an option without the Linux subsystem

do not need a full linux subsystem such as WSL.
i use cygwin, in which linux apps are compiled as .exe to run native on windows.

rsync.exe -r -vv --whole-file --itemize-changes /cygdrive/d/zork/src/ /cygdrive/d/zork/dst  
.d          ./
>f..T...... file.ext
total: matches=0  hash_hits=0  false_alarms=0 data=1

sent 117 bytes  received 105 bytes  148.00 bytes/sec

---

@Drexel

The same.
I think because my external storage is exFat file system

did you try --modify-windows=1s or --modify-windows =2s ?

---

@Drexel

I am under Windows,

on windows, for the past 10+ years, i use the following, both offer command line, GUI, log file, checksums.

• fastcopy
• second copy

---

@Drexel

robocopy

is a poor choice, as it cannot verify file transfers using checksums.
it has some advanced features, no other product has but you do not need them.