Macos/Box: "Failed to copy" on big files

Suspected Bug
1

What is the problem you are having with rclone?

Big files are failing to copy. Here is the error:

2025/04/03 09:33:18 ERROR : data/xxx/xxxx/GX010019.MP4: Failed to copy: multi-thread copy: failed to write chunk: expected to write 67108864 bytes for chunk 0, but wrote 300419718 bytes

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

rclone v1.69.1
- os/version: darwin 15.3.2 (64 bit)
- os/kernel: 24.3.0 (arm64)
- os/type: darwin
- os/arch: arm64 (ARMv8 compatible)
- go/version: go1.24.0
- go/linking: dynamic
- go/tags: none

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

Box

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

rclone sync "tom-box:/some_folder/my subfolder/folder" destimation-folder --max-size 0.6G -P --order-by="size,mixed,50"

The rclone config contents with secrets removed.

~/D/active [2]> rclone config show
[tom-box]
type = box
box_sub_type = user
token = {...}

A log from the command with the -vv flag

There are too many file names to edit.  I can't give those out.
2

welcome to the forum,

too soon to call this a bug...
need post a debug log, including the top 20 lines.

maybe try --multi-thread-streams=0

pick one trouble file, grep the debug log, post the output. can redacted the filename as file.ext

3

--multi-thread-streams=0 fixed it!

Here's a portion of the log file with path names changed:

subfolder" "destination-folder" "--max-size" "0.6G" "--order-by=size,mixed,50" "-vv" "--log-file=mylogfile.txt"]
2025/04/03 10:01:30 DEBUG : Creating backend with remote "tom-box:/folder/subfolder"
2025/04/03 10:01:30 DEBUG : Using config file from "/Users/me/.config/rclone/rclone.conf"
2025/04/03 10:01:39 DEBUG : fs cache: renaming cache item "tom-box:/folder/subfolder" to be canonical "tom-box:folder/subfolder"
2025/04/03 10:01:39 DEBUG : Creating backend with remote "destination-folder"
2025/04/03 10:01:39 DEBUG : fs cache: renaming cache item "destination-folder" to be canonical "/Users/me/Documents/active/destination-folder"
2025/04/03 10:01:39 DEBUG : conductors: Directory modification time the same (differ by 0s, within tolerance 1s)
2025/04/03 10:01:39 DEBUG : Added delayed dir = "conductors", newDst=conductors
2025/04/03 10:01:39 DEBUG : TEST_LOG.xlsx: Size and modification time the same (differ by 0s, within tolerance 1s)
2025/04/03 10:01:39 DEBUG : TEST_LOG.xlsx: Unchanged skipping
2025/04/03 10:01:39 DEBUG : checklists.pdf: Size and modification time the same (differ by 0s, within tolerance 1s)
2025/04/03 10:01:39 DEBUG : checklists.pdf: Unchanged skipping