Crash using rclone serve webdav proton-drive

Help and Support
1

What is the problem you are having with rclone? I'm trying to use rclone as a webdav interface to Proton Drive. The attempt fails with

`panic: runtime error: invalid memory address or nil pointer dereference`

I'm new to both rclone and webdav. Ubuntu 24.04.4 LTS

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

rclone v1.75.1
- os/version: ubuntu 24.04 (64 bit)
- os/kernel: 6.8.0-138-generic (x86_64)
- os/type: linux
- os/arch: amd64
- go/version: go1.26.8
- go/linking: static
- go/tags: none
```

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

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

Paste command here```rclone serve webdav --vfs-cache-mode full Proton:/```

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

Paste config here```[Proton]
type = protondrive
username = bdobby@pm.me
password = XXX
otp_secret_key = XXX
2fa = 822569
client_uid = XXX
client_access_token = XXX
client_refresh_token = XXX
client_salted_key_pass = XXX
### Double check the config for sensitive info before posting publicly
```

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

```
2026/09/06 13:42:53 NOTICE: proton drive root link ID '': 401 GET https://drive-api.proton.me/core/v4/users: Invalid access token (Code=401, Status=401), Attempt 1
2026/09/06 13:42:53 ERROR : proton drive root link ID '': 401 GET https://drive-api.proton.me/core/v4/users: Invalid access token (Code=401, Status=401)
2026/09/06 13:42:55 INFO  : proton drive root link ID '': poll-interval is not supported by this remote
2026/09/06 13:42:55 INFO  : proton drive root link ID '': vfs cache: cleaned: objects 0 (was 0) in use 0, to upload 0, uploading 0, total size 0 (was 0)
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x180 pc=0x27f38df]

goroutine 1 [running]:
github.com/rclone/rclone/cmd/serve/webdav.newWebDAV.func1()
	github.com/rclone/rclone/cmd/serve/webdav/webdav.go:271 +0x1f
github.com/rclone/rclone/cmd/serve/webdav.newWebDAV({0x3460100, 0x5599220}, {0x3484950, 0x65639415c0}, 0x55759c0, 0x656455f9b0?, 0x2452fea?)
	github.com/rclone/rclone/cmd/serve/webdav/webdav.go:297 +0xb22
github.com/rclone/rclone/cmd/serve/webdav.init.func1.1()
	github.com/rclone/rclone/cmd/serve/webdav/webdav.go:210 +0x54
github.com/rclone/rclone/cmd.Run(0x0, 0x0, 0x5531c80, 0x656455fbf8)
	github.com/rclone/rclone/cmd/cmd.go:255 +0x125
github.com/rclone/rclone/cmd/serve/webdav.init.func1(0x5531c80, {0x6563cb02c0?, 0x1?, 0x3200dfb?})
	github.com/rclone/rclone/cmd/serve/webdav/webdav.go:209 +0xaa
github.com/spf13/cobra.(*Command).execute(0x5531c80, {0x6563cb0280, 0x4, 0x4})
	github.com/spf13/cobra@v1.10.2/command.go:1015 +0xb14
github.com/spf13/cobra.(*Command).ExecuteC(0x5521f80)
	github.com/spf13/cobra@v1.10.2/command.go:1148 +0x465
github.com/spf13/cobra.(*Command).Execute(...)
	github.com/spf13/cobra@v1.10.2/command.go:1071
github.com/rclone/rclone/cmd.Main()
	github.com/rclone/rclone/cmd/cmd.go:539 +0x31
main.main()
	github.com/rclone/rclone/rclone.go:14 +0xf
2026/09/06 14:23:30 DEBUG : rclone: Version "v1.75.1" starting with parameters ["rclone" "-vv" "--log-file=rclone.log" "serve" "webdav" "--vfs-cache-mode=full" "Proton:"]
2026/09/06 14:23:30 DEBUG : Creating backend with remote "Proton:"
2026/09/06 14:23:30 DEBUG : Using config file from "/home/brian/.config/rclone/rclone.conf"
2026/09/06 14:23:30 DEBUG : proton drive root link ID '': Has cached credentials
2026/09/06 14:23:40 NOTICE: proton drive root link ID '': Get "https://drive-api.proton.me/core/v4/users": dial tcp: lookup drive-api.proton.me on 127.0.0.53:53: read udp 127.0.0.1:41252->127.0.0.53:53: i/o timeout, Attempt 1
2026/09/06 14:23:47 DEBUG : proton drive root link ID '': Used cached credential to initialize the ProtonDrive API
2026/09/06 14:23:47 INFO  : proton drive root link ID '': poll-interval is not supported by this remote
2026/09/06 14:23:47 DEBUG : proton drive root link ID '': vfs cache: root is "/home/brian/.cache/rclone"
2026/09/06 14:23:47 DEBUG : proton drive root link ID '': vfs cache: data root is "/home/brian/.cache/rclone/vfs/Proton"
2026/09/06 14:23:47 DEBUG : proton drive root link ID '': vfs cache: metadata root is "/home/brian/.cache/rclone/vfsMeta/Proton"
2026/09/06 14:23:47 DEBUG : Creating backend with remote ":local,encoding='Slash,Dot',links=false:/home/brian/.cache/rclone/vfs/Proton"
2026/09/06 14:23:47 DEBUG : :local: detected overridden config - adding "{8un-i}" suffix to name
2026/09/06 14:23:47 DEBUG : fs cache: renaming cache item ":local,encoding='Slash,Dot',links=false:/home/brian/.cache/rclone/vfs/Proton" to be canonical ":local{8un-i}:/home/brian/.cache/rclone/vfs/Proton"
2026/09/06 14:23:47 DEBUG : Creating backend with remote ":local,encoding='Slash,Dot',links=false:/home/brian/.cache/rclone/vfsMeta/Proton"
2026/09/06 14:23:47 DEBUG : :local: detected overridden config - adding "{8un-i}" suffix to name
2026/09/06 14:23:47 DEBUG : fs cache: renaming cache item ":local,encoding='Slash,Dot',links=false:/home/brian/.cache/rclone/vfsMeta/Proton" to be canonical ":local{8un-i}:/home/brian/.cache/rclone/vfsMeta/Proton"
2026/09/06 14:23:47 INFO  : proton drive root link ID '': vfs cache: cleaned: objects 0 (was 0) in use 0, to upload 0, uploading 0, total size 0 (was 0)
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x180 pc=0x27f38df]

goroutine 1 [running]:
github.com/rclone/rclone/cmd/serve/webdav.newWebDAV.func1()
	github.com/rclone/rclone/cmd/serve/webdav/webdav.go:271 +0x1f
github.com/rclone/rclone/cmd/serve/webdav.newWebDAV({0x3460100, 0x5599220}, {0x3484950, 0x198b7bf6d740}, 0x55759c0, 0x198b7cbed9b0?, 0x2452fea?)
	github.com/rclone/rclone/cmd/serve/webdav/webdav.go:297 +0xb22
github.com/rclone/rclone/cmd/serve/webdav.init.func1.1()
	github.com/rclone/rclone/cmd/serve/webdav/webdav.go:210 +0x54
github.com/rclone/rclone/cmd.Run(0x0, 0x0, 0x5531c80, 0x198b7cbedbf8)
	github.com/rclone/rclone/cmd/cmd.go:255 +0x125
github.com/rclone/rclone/cmd/serve/webdav.init.func1(0x5531c80, {0x198b7c29c5c0?, 0x1?, 0x3200dfb?})
	github.com/rclone/rclone/cmd/serve/webdav/webdav.go:209 +0xaa
github.com/spf13/cobra.(*Command).execute(0x5531c80, {0x198b7c29c380, 0x4, 0x4})
	github.com/spf13/cobra@v1.10.2/command.go:1015 +0xb14
github.com/spf13/cobra.(*Command).ExecuteC(0x5521f80)
	github.com/spf13/cobra@v1.10.2/command.go:1148 +0x465
github.com/spf13/cobra.(*Command).Execute(...)
	github.com/spf13/cobra@v1.10.2/command.go:1071
github.com/rclone/rclone/cmd.Main()
	github.com/rclone/rclone/cmd/cmd.go:539 +0x31
main.main()
	github.com/rclone/rclone/rclone.go:14 +0xf
```
2

yeah that 401 on drive-api.proton.me usually means the protondrive token died before the nil panic. id try rclone config reconnect Proton: (or wipe the client_* bits and redo 2fa) and see if serve still blows up after auth is clean.

if it still nil-derefs after a good login, that smells like a bug around root lookup on serve webdav + protondrive. worth a github issue with the -vv log you already have. vfs flags probably arent the first lever here