I had fixed some tags on some of my files. A while later, I tried closing foobar, which for some reason didn't respond and crashed. When I opened foobar again, I noticed all the changed tags had reverted to their orignal values.

Is this normal? Why does it happen?

If it's not normal, why could it have happened?

I've never noticed this happening before, but me not noticing doesn't mean it hasn't happened.

If the tag belongs to a file that's currently being played, then tag updates are suspended until the song finishes.

IMHO, I think losing data in a crash is within normal limits.

No files were being played. I successfully changed the tags, and foobar closed minutes after the tags had been saved. Shouldn't these tags stay saved, despite a crash?

I believe that I can corroborate his story, it seems that this has happened to me too. After a 3 hour long tagging session, no less.

Same here. Everytime I've get a crash, tags written in this session were lost.

Have you tried selecting the files in foobar and right-clicking and hit "Database->Reload info from files"? Foobar crashing won't change the files tags, it just won't save the updates to foobar's database.

Yeah, I did
Sometimes I was able to get some tags back this way, but not always. I don't get why, because tags should be written into the file, what you say makes sense, only database shouldn't be updated if fb2k crashes and doesn't closes properly.

I don't suppose you have 'block tag update operations' (in database preferences) checked, do you? :x

Nope.

This has happened to me as well, which is why I always save any changes to playlists after modifying them in any way. That way, all I have to do is remove the current playlist and reload the saved version in the event that Foobar crashes for some reason.

I believe this happens because Foobar will normally write any changes to tags or track order to the database. When Foobar crashes, this update doesn’t take place and you are left with your tags/playlists in the order they were the last time it shutdown properly. However, any changes made to tags should still be there, but will only refresh when you play the track again or reload the metadata from the file.

So, the moral of the story is to always save your playlists after making any significant changes to them. You never know when disaster will strike.

That makes sense, but in my case, I'm pretty sure that didn't happen. Reloading the data from the file didn't do any good. However, by now I've forgotten exactly what happened, so I might be incorrect. I'll find out next time.