Comment # 4 on bug 1228876 from Christophe Marin

(In reply to Alexander Sanderson from comment #3)
> Okay, so after my computer being in sleep for a bit, the issue happened
> again. Tried `QML_DISABLE_DISK_CACHE=1 systemsettings` and it fixed it.
> 
> What's a more permanent fix, should this occur again?

None yet, but you can remove ~/.cache/systemsettings/qmlcache when you get the
issue.