I have been running Duplicati for several years with no problems until recently. I run two identical backups, one to an external USB drive and one to Backblaze. The USB drive backup is working perfectly, the Backblaze backup is generating 2672 warnings such as this:
2025-04-08 20:50:28 -04 - [Warning-Duplicati.Library.Main.Operation.Backup.FileBlockProcessor.FileEntry-PathProcessingFailed]: Failed to process path: C:\Users\bob\Desktop\NewMame\MAMEUI64.0.214\whatsnew.txt
UnauthorizedAccessException: Access to the path ‘\?\C:\Users\bob\Desktop\NewMame\MAMEUI64.0.214\whatsnew.txt’ is denied.
On the Duplicati “Home” page (from the GUI), it says “Last successful backup” was good. But it is obviously failing to backup 2672 files.
I am ONLY getting the UnauthorizedAccessException when I run the Backblaze backup. These same files backup without errors or warning when I run the USB backup.
I am running Windows 11 24H2. I have upgraded to Duplicati - 2.1.0.5_stable_2025-03-04. I have FIOS internet.
Tried:
Repair database.
Delete and repair database. (It took 1.5 days)
Revert to previous version of Duplicati. Still did not work so went back to latest release.
Checked permissions on files and they are OK.
Rebooted system.
I don’t understand why the backup works for the USB drive but fails on the same files for the Backblaze backup. I suspected the Duplicati update was causing the problem, but backing up to the last release did not solve the problem. My backup solution no longer works and I could use some help to get it going again.
Anything more on “suddenly broke” in topic title? Any known changes done then?
Grasping at straws somewhat, are both running in the same Duplicati GUI process which may or may not be running as the user accessing it through a web browser?
Maybe that Warning should become an Error. The dev might have an opinion on it.
shows it’s a pretty generalized complainer. Not sure all are as major as this one.
Is there any pattern to them, e.g. in a certain area? Random fail would be weirder.
You could certainly try a small Backblaze backup with one file, e.g. the one shown.
If need be, I suppose you can install Sysinternals Process Monitor to watch the file which might confirm that it’s being rejected below Duplicati. You could then add the file as an exception to your virus scanner in case that’s gone wrong, but why it then works to the USB drive but not to Backblaze from same Duplicati (yes?) is strange.
One possible explanation is in timing, e.g. if the file is already up to date in a given backup, then it doesn’t get read through. Some other (earlier?) backup may read it.
Thanks for your reply. Here are the answers to some of your questions.
I am running both the local and the cloud backup from the same user (not administrative) process. They are scheduled backups that run at different times. I get the same result if I run the cloud back manually from the GUI.
I do think it should be flagged as an Error instead of a Warning if it is not caused by a “file in use” or a locked file (which seem to create different specific error messages).
I’m not sure yet if there is a definite pattern. However, a lot of these seem to come from files that are on folder on my desktop (c:/users/bob/desktop). The Show Logs command only shows a small number of these files so I am not sure. I will try to check next time by doing a Show Logs Verbose from the GUI.
I will try your suggestion of doing a one file backup of one these files. The files that I have seen so far in the Warning messages are files that have not changed in a long time, so there should not be any problem with them changing during the backup session.
The backup destination is completely irrelevant to the backup code that reads the files, so the only explanation I can think of is that they are running in different processes, or that something else (anti virus?) is accessing the files at the same time.
The exception is specifically UnauthorizedAccessException which should precisely mean that the current user (that which is running Duplicati) does not have access to the file. Seeing that Duplicati can enumerate the folder (to get the file name) it must be a permission on the file. Can you check that the permissions look plain?
The logic is that it is common enough that there are “flukes” were something prevents reading a file. Most such errors are transient, so they are treated as warnings.
We don’t currently have any classification of errors (permissions, file locked, I/O error, etc), so we consider all errors to be transient, which is not always true.
Turning off antivirus
Monitored with ProcMonitor – nothing unusual (no errors shown)
I checked that the user and admin accounts have “Full Control” permissions on the file.
Finally, I decided to remove Duplicati, then deleted related directories, then reinstalled. It took 4 days to rebuild the databases for the remote and local backups.
I completed the backups with no errors. However, lots (4864) of warnings: “UnauthorizedAccessException: Access to the path …” These appear to mainly on files within my Desktop. But since it only shows a limited number when viewing the logs, I can’t be sure if it just the Desktop.
On the Backblaze backup I get 4863 warnings. : “UnauthorizedAccessException: Access to the path …”
Although the backup on the home page shows both being completed successfully, I wanted to make sure my files are really backed up. So I tried to do a restore just to make sure that I see a good list of files to restore. Duplicati waits several minutes and gives me the follow error “database is locked database is locked” (Yes, it is repeated twice)