If its showing up in the Duplicati UI then it should be backed up or removed from showing for sure. That shouldn't be up to the user to deal with two minds.

But, I'm not sure what's going on here entirely. I would have to think that its failing to gain required access during the file crawl and moves along skipping it.

Also side note that I will not discuss, and you might not like it, but you shouldn't let 2 years or even 1 go by without checking and/or starting fresh your backups. There's no backup application that you shouldn't continually check. You should also use at least two different applications. Your business is at stake and you put all your eggs in one basket.

The UI green check/red X doesn't show more complex inclusions/exclusions especially regex ones. This is a deficiency for sure, but might be difficult to solve. Some filters must be evaluated at time of backup.

@Xavron Thanks for seeing the issue for what it is and recognizing it shouldn't be up to the end user. The other thread I referenced hints at the root cause and the solution (requiring a custom exception) is in the last post which helped me get around the issue for now.

As for your advice regarding backups, you shouldn't make assumptions and then state you wont discuss them, I have three copies of all files, the live versions, the nextcloud versions and the duplicati versions, and I also take a yearly offline backup to an 8TB drive of all critical stuff. I also use the Duplicati restore on a regular basis (at least every month or two) so I knew my backups were running and retaining as they should.... the one and only issue is that the software shows it's backing something up, that it actually isn't. I shouldn't have to restore every file I'm backing up on a regular basis just to check that it's backed up properly. Please don't try to blame this on a users lack of understanding of how backups should be run and tested. Enough said.

"As for your advice regarding backups, you shouldn't make assumptions and then state you wont discuss them,"

Not an assumption. "it's dumb luck that I didn't have a complete failure and need those files! My business would have folded." You would then only have one backup. Its not an issue if you have two or three other backups (each using a different application) unless you somehow managed to destroy or lose all of them at once. (edit: in which case it wouldn't matter anyway lol) So no, I will not discuss it further :-)

Also, this issue is really the same as to work with hidden files, etc kind of issue. It shouldn't be treated any differently. Either it should in whole or it shouldn't in whole. It is the way I develop stuff, but I do disagree at times with devs, so if they choose to see it the same way or not that's up to them. As in no problem. I see it the same way as you.

@devs. At least I would go by seeing if the files could be backed up. If just not possible, then put in a check during the listing of the files & folders in the Duplicati file browser to eliminate them from being listed or something like that. If neither could be done then there's a red text warning situation with the file browser so the user knows its funky. Temporary measures could be done too. But, you might see some other way =)

Also have to deal with the catch all User folder or whatever. If its not backing up stuff under it then it definitely needs user warning about that.

I do assume here that there's no message after a backup runs. I didn't look if that was something happening there. Duplicati loves having messages after so I'd be surprised if there wasn't already something happening here for the user in knowing. And if there is a message then there's already a nice check in place. Though needing a listing fix at the very least.

@Xavron I agree it's a bit like hidden files, even down to the dedicated checkbox to not exclude System files, but then it silently excludes this specific type of system file still (which is what the other thread still called them), that's where it becomes a little more serious. The solution is to manually add "Exclude Filter Group" -> "System Files".

@drwtsn32x A warning when selecting a folder tree that includes files/folders that will be excluded without manual intervention would be great, but from a programming perspective might be more work than is necessary. If it didn't happen at the folder tree selection stage but instead at Submit / "Next" with a warning message indicating that there are resources that will be excluded... or even a quick confirmation step which lists the selected files/folders that are going to be excluded and a prompt "I agree, these should be excluded" with an alternate option with an instructions on how to include them, or an simple option to say, "Please include these files anyway" that adds the Exclude Filter Group rule in the background.

This would make the whole process more friendly and transparent, and more capable of dealing with potential edge situations without adding a lot of work.