Error "Unfortunately backup has stopped": How do I fix?

[AC Question]

When I click the app Backup it says unfortunately backup has stopped

 

[Laura Knotek]

Welcome to Android Central.

What device do you have, and what version of Android is it running? What type of backup are you doing? Are you trying to backup prior to performing a factory data reset? Is your device rooted?

 

[Antoine Rachoine]

During backup from Smartswitch, my Galaxy S6 Edge displays: unfortunately backup and restore agent has stopped. Plz assist.

 

[LexxyT]

I'm getting the exact same thing. Anyone have any ideas?