Activated gnome extension (just default) break my desktop search.
I see an error in the KSystemlog for the Gnome extension Appfolders Management extension. After uninstalling the application
pamac remove gnome-appfolders-manager the search started working again.
Welcome to the forum! 
Neither your topic title nor your post are adequate to help others help you.
What log?
There’s no such thing. gnome-appfolders-manager is a program, not a GNOME Shell Extension.
Please see:
Thank you!
Thanks for pointing out the misstake in the post
That’s neither in the repos nor the AUR. How did you install it? Either way, it’s a very old, incompatible extension.
gnome-appfolders-manager has nothing to do with anything here.
KSsytemlog, eh? Are you sure you’re using GNOME? 
I’m unlisting this as all this topic will do is confuse others. You installed an incompatible GNOME Extension, it broke GNOME Shell. Removing it solved the issue.