The version is quite old - 2.0.2.1_beta_2017-08-01, and I’m guessing the right thing to do is just upgrade and try again. The files at the backup destination are .zip – a little over 62,000 of them. I have tried running repair, but it doesn’t solve the problem.
That said, the reason why I haven’t is because this backup runs on an ancient CentOS 7 machine that does not like getting updated from non-core repos or with out-of-band packages. I was hoping someone would be able to say “oh, that happens when XYZ, just click this button!”, but I guess I’ll just have to rip off the band-aid. Or maybe run duplicati in a more modern docker container.
I appreciate the help!