Looks like this might be a problem within my Windows installation. Noticed also several other issues in the context of saving images, system repair can not repair the system:
sfc /scannow => Der Windows-Ressourcenschutz hat beschädigte Dateien gefunden, die teilweise nicht repariert werden konnten.
dism /Online /Cleanup-Image /ScanHealth => sticks at 100%, does not provide a result
Upgrade to Win 10 1903 did not fix this today.
Probalby sooner or later a new install from scratch will be needed… Thanks anyway.
I’m sorry to hear about your Windows woes. I don’t know if you’re inclined to worry about Duplicati now. If you are, then Warning: sqlite-journal errors 1400 was possibly a similar problem (except maybe easier to identify) where a file being actively changed during backup triggers that problem, and possibly also yours.
If you happen to have specially installed as a Windows service (or are otherwise running on Administrator privileges), –snapshot-policy=Required would prevent Duplicati backing up Duplicati’s database while it’s actively changing. Another option to avoid that would be to Edit in an exclude Filter for files beginning with your backup’s Database path. This will avoid the .sqlite-journal file that often seems to be the culprit. Commonly the DB isn’t intentionally backed up, but just gets backed up in wholesale backups, e.g. of C:\
Because above is a guess, logs such as default backup log, or live log at About --> Show log --> Live, or setting –logfile might catch some other message or path that would help to figure out what the issue was.
Even better (if you’re willing to take a small risk of filenames being seen), is linking a database bug report.