Trying to log in to Plasma as root gives a dialog that says:
"Could not start D-Bus. Can you call qdbus?"
with a button that says "okay"
Clicking it results in nothing else happening; just stuck with a red screen.
Please report this upstream but i don't think this is a bug.
It's certainly a bug, as this used to work, and it should work (even if it's not recommended for general use), and it really sounds like a possible packaging problem to me.
Note that Lewis got the same exact error logging into Plasma from GDM:
I assume that was even as a regular user.
is it still valid with plasma 5.8.6 ?
just tested, this is now fixed in cauldron.
I can confirm that this is fixed. Thanks.