All of a sudden this morning my extensions stopped working. The extensions preference pane is empty and says "No extensions".
All the extensions are left in
~/Library/Safari/Extensions, and if open one of them to install it says (roughly translated):
Safari can not install this extension
An error occured when the ”NinjaKit” extension was installed.
I tried restoring the entire
~/Library/Safari folder and
~/Library/Preferences/com.apple.Safari.plist from a backup from yesterday when everything was working fine, but that did not solve it.
The issue may stem from wrong permissions somewhere, since if I try to edit the Extensions.plist file manually it says "Unlocking failed for an unknown reason." when I try to save it. I tried
sudo chmod -R 0777 ~/Library/Safari/Extensions but that did not solve the issue either. The file is not locked from the "Get Info" view in Finder.