For months I have had the problem that the backup is still “in progress” while in reality it has finished this continues until it HA is restarted at which point a message indicates that the last backup failed. I have tried several fixes suggested here but the problem persists. It also sometimes shows 'backing up add-ons" when addons are not selected for backup 
The real downside is that with recent changes I can’t install HA updates because a “backup is in progress”. So I wait for an add-on or integration update which circumvents that message and allows a restart. Then I can update HA!
Has anyone got a suggetion on how to reset the backup process?