I have assembled a new AMD, Mate 20.04 system with two user profiles. With the exception of the second user the new computer is configured the same as our other computers (i.e. desktop, apps loaded, firewall, home folder on separate drive etc), including the settings in Deja-Dup. The backups on all systems are saved on their respective external USB drives being mounted at mnt.
When I ran a Deja-Dup backup-restore test it failed to restore the deleted folder giving an error message indicating the restore failed because of an unknown error. The restore process appears to correctly step through the required windows to the point where a password is entered and then a short time after the password is entered the restore fails.
I have tried installing Deja-Dup via the terminal and from the Mate Software Boutique, using different external storage drives, backing from the home folder and from the home folders storage drive located at mnt. Our other computers all backup and restore successfully with Deja-Dup pointed to the home folder.
I tried reinstalling Deja-Dup, but found it kept all of the previous installs settings. So to get a fresh Deja-Dup install (and new password) I have found I need run sudo apt purge deja-dup and also delete ~/.cache/deja-dup file and then run dconf reset -f /org/gnome/deja-dup/
Any suggestions-ideas appreciated