Nothing. Wallpapers are managed by a (bad) system extension. Log out or reboot and it should start again.Got this, what have I done?
Thank you,Probably some corrupted files/folders used by the Wallpaper extension are causing the error.
You could try to run Onyx maintenance https://titanium-software.fr/en/onyx.html
How did they solve this?Update!
Problem sorted today, contacted apple 2 days ago, problem wasn't resolved so they gave me a phone call today ,
Problem sorted in minutes, apparently, just a software problem
A very happy customer here ............. well done apple !
............... Gary