Hi all, unfortunately I have installed unity, now no longer possible to have the default budgie lock screen ? I have make some research on google and here with no result, any ideas. THX!!
Sorry no idea why unity stamps all over budgie 
bad bad unity
Budgie’s lock screen is gnome-screensaver so at a guess try reinstalling that package
sudo apt install --reinstall gnome-screensaverthx works fine, just impossible the change the lock screen pictures. remain the gnome ones!?
In settings - background you have the ability to change the lock screen image.
If it doesnt work then I am afraid that is unity messing with your system. Nothing we can do about that.
Hi, I have a question connected with the same topic here so I will post it here and hopefully someone will see it 
I want to change lock screen background in Ubuntu Budgie 20.04. I have found a few answers on google saying I should change some ubuntu css file but I wanted to check with you guys if there is easier way to do that. For example in the answer here by @fossfreedom that option should be available directly from settings. But I don’t see anything there. Here is the screenshot, can you tell me where to find that option?
Yeah - that answer was written back in 2019 when Settings Background had the ability to set independently the background picture for the lock screen & user session.
Now they are tied together.
If you change the dconf key value (via dconf-editor) to the path to your picture then your lockscreen picture will be different from your user session
org.gnome.desktop.screensaver picture-uriThank you! Great, it works and it’s easy (I already had dconf-editor installed). Cheers!