multiple mobile device syncs "failed initial scan" at once

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Suggestions on how to proceed for no data loss?

I’ve already encountered several problems with Syncthing after updating recently, but my mobile (Android) devices were still syncing with my PC until sometime earlier today. I count at least 6 mobile devices, some with multiple folders all reporting the following:

2025-09-19 19:19:59: Failed initial scan (error=“folder marker missing (this indicates potential data loss, search docs/forum to get information about how to proceed)”

Oddly, several of these mobile devices which are reporting ‘failed initial scan’ have not been on for several days or weeks, so I know the problem is occurring on the PC side.

I have restarted Syncthing 2 or 3 times with no change.

On one of the Android devices, I added to the root folder a .sdfolder, as an AI suggested this is what commonly resolves the issue. I restarted Syncthing on the Android device 2x, also to no effect on the PC.

I am running version 1.28.1 of Syncthing from the FDroid repository, and SyncTrayzor 2.01 with Syncthing 2.09 on a Windows PC.

For one of the earlier problems, I think it was a corrupted database, which may have been resolved by removing and then adding back a synced folder. It’s large, so I’m still waiting to see if this fully resolves that issue.

I’m ready to completely reinstall Syncthing, especially if someone can suggest a way I can acquire a text listing all my settings.

Thank you for any help.

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Where is the error message displayed? I don’t quite follow your description. Can you post a screenshot or exact copy of the message?

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I guess part of the confusion is that I typically use SyncTrayzor’s browser, which seems to notify a bit more directly than the vanilla Syncthing.

Regardless, I found the potential culprit (and bug?). It seems Syncthing deleted the directories on its own. I went into each of the failing directories, added a folder named “.stfolder”, hit “Rescan”, and the problem resolved.

2025-09-19 16:31:23 INF Deleted directory (folder.label=“Home: Sync” folder.id=qkhzz-wtfo2 folder.type=sendreceive dir.name=A70\Transfer.stfolder dir.permissions=0755 log.pkg=model)

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First a bit of Syncthing nomenclature:

  • Directory: A place in the file system tree where you can put other directories and files.
  • Folder: An item which is created in Syncthing which can be shared with other devices.

No, I bet that something else deleted the “.stfolder” directory. Syncthing only deletes it when you are deleting the Syncthing folder.

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