Backing up to external HDD

I have my laptop backup going to an external HDD daily. Usually, the laptop is in my office with the HDD connected via USB. Sometimes when I move the laptop and disconnect the HDD, the next backup fails and it hangs up on random files and I am not able to stop the backup even though there doesn’t appear to be any progress being made. It hasn’t happened enough for me to know if the failed backup started without the HDD connected or if it was just that the HDD was disconnected and reconnected between backups, (hard for me to think this would create any issues).

Would like to know how to ‘kill’ the backup that is hung up as well as knowing why this is happening at all.

Quite possibly it’s deep inside Windows therefore not very answerable here. You could install Sysinternals Process Monitor to look for accesses to the external drive. It might be resource intensive if run a long time.

Assuming that means source files (as seen in the GUI), it takes some of those before there’s enough to begin writing destination files, so maybe that winds up at seemingly random source. Watch destination activity in About --> Show log --> Retry, or (if issue is too rare), set up a log-file at log-file-log-level=retry.

There’s a chance that you can get some data after it’s already hung, at About --> Show log --> Profiling. That’s the best level, but logs tend to get huge, so I’m not going to suggest right away to set that log file.

What Windows version is this? Do you use “Safely Remove Hardware”? Windows 10 now lets you pull out USB drives without ‘safely removing’ them discusses that change and some of the configurations behind it.

Alternatively, do you sleep the laptop before disconnecting? Possibly that would be less likely to get a hang.

One can always kill all the Duplicati processes seen in Task Manager, but it risks corrupting the database.
Assuming you are on Beta and not the newer Canary, best plan is “Stop after current file” before a hard drive unplug. “Stop now” was a little buggy in, but I think it was a database issue not a hang…

You might have to do some testing on a non-critical backup to answer questions such as whether starting the backup without the HDD connected leads to problems. Right now there seem to be a lot of unknowns.