Comment 4 for bug 1770929

I had an error with the same look in the last couple of days with the daily backup:

"Failed with an unknown error.
Traceback (innermost last):
  File "/usr/bin/duplicity", line 1555, in <module>

I found my external drives became read-only. I have a dual-boot Win10/Ubuntu system. Reboots/clean exit of Windows did not help, drives were still read only, and the backup process remained broken, but I realized that the Fast Boot option is reactivated. It should have been the April 2018 Windows update I just installed some days before... After I turned Fast Boot back off, backup has completed, seems to be perfect again.