Troubleshooting System.IO.IOException

In the last two days, some of my backups have began to fail with “System.IO.IOException: Rakenne vaatii puhdistusta”. Since the message stays in Finnish even when I change language to English in the Web UI settings, I assume this message comes from .NET/Mono. If I translate the part in Finnish word-by-word, it says something like “Structure requires cleanup”.

The problem with this kind of trouble is that all I get is this message (and the call stack), nothing else. I don’t know what to check. I get the same message from backup, verify, repair and list-broken-files. Other commands I have not found reasonable to try out.

This problem has occurred with two of my backup sets. A third one complained about broken files, and I got it fixed by running purge-broken-files. In that case, the message was clear enough. But this other one is not. I wish Duplicati could provide me a little more help for trouble-shooting.

The problem appeared in Duplicati - on Ubuntu 20.04 and I am making my backups onto an external disk. Until now, it has been working fine. I am afraid this error could indicate a problem with the disk, so I don’t believe that upgrading Duplicati right now to the latest version would help.

Before buying a new disk, however, I would like to see if someone could help me clarify what really is going on.

When Duplicati encounters a catastrophical error, it just displays the error coming from the operating system (like most software do). In your case the operating sytem is probably setup to use Finnish.
From the context, it probably means that your external disk needs repair (fsck or whatever)

Before your reply, I had already done e2fschk and then tried to find a way to fix the two duplicati backup sets. I ended up running a combination of repair (with and without --rebuild-missing-dblock-files), purge-broken-files, verify and backup, but they all complained until I deleted one offending file in each of the two backup sets, and finally got the both backup sets running a backup without errors. Now, of course, I don’t know what is missing from their history. Unfortunately, I forgot to check the age of the files that got purged, but the two deleted files were from today, so probably I didn’t lose anything with them two. It is the purge-broken-files that may have wiped out something essential.

Well, situation is over for now.