They have to be set up manually with –log-file. Adjust wordiness with –log-file-log-level. My own practice is to keep one going with as much detail as it can do because if something breaks it’s helpful both personally and to maybe get code changed for me and everybody. That’s more than I’d ask of the typical user though. Some lower level like Information or Retry might be worth keeping up (while not making too huge a log file).
Agreed on that, however there are smaller test cases in line for problems that are impacting lots of people. Maybe support could set this up, and at least look into reasonable methods to recover as well as possible. Not saying there are enough support volunteers either, but developers up to debugging this may be rare…
@warwickmm has been adding some code fixes for Duplicati temp dup-xxxx files not being deleted, but I don’t know if they cover your case. Some of the prior leftovers didn’t involve a cancel, but just happened…
A rewrite of repair/recreate began in December, I believe with focus on making repair succeed more often. Time will tell how successful it is, and I have no details on its progress or its ambitions. There will probably always be non-repairable situations, but there’s clearly a lot of room for improvement on what it now does.
Duplicati’s rather complex algorithms are more than humans can manually perform or clean up when they run into problems, so I share your concerns about the available tools sometimes not being sufficient either. This is why I advise people to treat Duplicati as what it is – beta software which frequently does a great job but occasionally breaks and is hard to fix. Sometimes restarting a new backup is the way out if acceptable. My own practice is to not put Duplicati into situations where a breakage would be a tremendous loss to me. I also take image backups around Windows’ twice-a-year updates, adding additional protection for old files.
Do you by any chance have another Windows machine that’s not running Duplicati that could work on the failure situation (possibly including the old saved database) while you get your main machine going again? There are also ways to get multiple Duplicati databases on one machine, e.g. by using it in different users.