I rebuilt an array on one of my machines recently and was presented with the “folder marker missing” error.
The message says to search on the forums for next steps.
When I did so, the first/highlighted google result was “the .stfolder is just a regular folder, so you can just make a new one and the error will go away.”
This is, of course, terrible advice, because immediately after doing so, syncthing deleted all of the data in the other server’s folder and now neither machine has a copy of my data.
I’m not blaming a user for giving bad advice here, but “search the forums” is clearly not an appropriate message to give to the user because this is exactly the kind of thing that will happen. Official documentation is crucial for this.
Also, ideally, for common cases where this could happen, a simple UI resolution such as (for me) “Click here to restore all data from OTHER machines to this one.”
Yes, one has to properly do some research first instead of typing in the very first thing that catches the eye. This could be alleviated with a direct link from the error message.
In the docs we indeed don’t really make the dangers fully clear. We only mention it in two places (here and here)
Indeed, we should probably add a proper FAQ/entry in the docs regarding the specific error message “folder marker missing” that explains the various situations causing it plus the consequences of recreating it and then link to that. This has been brought up some time ago, though it apparently never happened, probably because no one wrote the PRs.
This is what happens when you remove and readd the folder from within syncthing, which is basically why the error message advises to search the forum, since it’s been mentioned here a few times.
I agree, pointing just to the forum with no more specific info is terrible advice. At the very least we should have an official doc article about it that we link to instead. Thanks @Nummer378 for working on making that happen!
Luckily, the data I lost in this case is all replaceable and it’s only a headache on a day that wasn’t going my way. But, I thought it best to bring this up because the next person to experience it might not be able to replace the data.
In my case, it was this thread that came up, with the highlighted text being scraped by google search (thanks, Google).
Admittedly, I wasn’t as careful as I should have been (aforementioned bad day and all). But if it can happen to me, it can happen to others, so I definitely support the bare minimum solution being to create a support page that is direct linked from the UI when this error occurs.