I’m returning to this thread after a long time because I happened to stumble on something. I came across this page: Connecting securely to Microsoft OneDrive with WebDAV :: WinSCP. It describes how to connect to OneDrive using WebDAV with WinSCP. I gave it a quick go, and it seems to work fine. However, it doesn’t work in Duplicati, returning a “Failed to connect: The remote server returned an error: (404) Not Found.” (message from the ‘Test connection’ button). A quick search suggests that WinSCP also had this issue but that they were able to fix it (WebDAV to OneDrive cause error :: Support Forum :: WinSCP).
Does anyone know if there is a particular reason that this approach does not work with Duplicati?
I gave it a go but it didn’t immediately seem to work. I kept receiving 404 Not Found errors (attempting a backup in a directory that should exist), with or without the flag set. I cannot completely exclude that I am setting things up incorrectly though.
It may be worth noting that I recently found some time and motivation to take a better look at the OAuthHandler, and ended up writing my own service (with significant help from your version, especially to figure out what Duplicati expected of the service). It ended up being an interesting project to try out some things that I had been wanting to try for a while anyway. So far, that approach seems to be working alright. As a result, it is less important to get things working in another way, though it’s still interesting.
Was the Test Connection feature removed? I migrated Duplicati from one PC to another yesterday and ran into trouble with OneDrive authentication. I eventually got it fixed, but couldn’t find the Test Connection functionality. That was pretty useful when it existed because you could test whether Duplicati could open the remote repo without having to run a full backup.
it moved up a bit on the new UI Destination screen:
It’s renamed, but I think it actually does more now…
About Duplicati → Changelog
Improved backend test function
This isn’t really by new UI, but new UI describes new test. Old was just a file list, basically a sanity test on the connection (like you said). New one exercises files.
2025-05-29 - 2.1.0.119_canary_2025-05-29
Better backend Test
The test feature has been updated to now check for write permissions, instead of just listing the remote folder. For ngclient, the Test check now uses this extended check to inform the user if there are files in the destination folder. This shows a warning if creating a new backup pointing to a folder with existing data, and a warning if attempting to restore from a folder with no files. If the write part fails for a test during the restore flow, this is not treated as an error in ngclient.
