Duplicati does not install or does not complete the backup

How do you try? IMO the new design is asking for trouble (in the name of security?) but try this:

You ought to have a tray icon that you can right click on. The special link is “emitted” to nowhere unless you started from a terminal, which seems extremely unlikely for the usual tray icon setup.

There should have been a first run popup message telling you about the new password scheme, however the number of changes in this Canary has resulted in ample bugs. See announce topic.