Filesystem Discovery no longer functioning on Windows 11

This feature used to work when I first started using Syncthing, so I’m not sure if it was a recent update that broke it (to either Syncthing or Windows).

Plain and simply, “Watch for Changes” is not functioning at all. When I make a change to a directory (add/remove a file from Windows into a folder that is synced), the changes are only reflected on the other devices (a galaxy S22 and Tab S9+) when I manually click the sync button in the browser (on Windows) for that particular folder.

I attempted to do this in reverse (modifying the same directory on one of the Android devices), and the results were immediate, so this looks to only be an issue on the Windows installation.

The periodic scan is still work as expected as well.

Syncthing Version: 1.27.4

OS: Windows 11 Version 10.0.22631 Build 22631

Browser: Chrome Version 122.0.6261.129 (Official Build) (64-bit)

What is your folder path? There is a known bug where file watching doesn’t work for drive root paths, e.g. D:, etc. There is no workaround or fix for it yet.

I’m aware of that bug, it’s not the root drive. As mentioned it was working previously, I’ve made no changes to the settings. Not sure if the app auto-updated though seeing that I’m on the latest version, it clearly must have.

It’s also not just one folder, but EVERY folder I have configured (all of which use file watcher) are not activating on directory changes.

This issue has been present for months now, however. I don’t use it often enough to have been bothered looking into it sooner. I had some time to do so and was not able to find a solution…

I think you could try doing some testing with a completely new folder. Change https://docs.syncthing.net/users/config.html#config-option-folder.fswatcherdelays to something very low, e.g. 1, then under “Actions → Logs → Debugging Facilities” enable “watchaggregator”, then try adding a single file to the folder and see what happens. You can also upload the debug log after doing so.