Symptoms

We constantly receive the following error in the K2 logs:
"87883361","2015-08-13 05:43:45","Error","General","24148","UMEmptyQError","K2DestQueue.RunDestQueue","24148 The User Manager 127.0.0.1 returned an empty queue.","anonymous","0.0.0.0","GLLDCSVQK2F02:C:Program Files (x86)K2 blackpearlHost ServerBin","87883361","c387cc5012794991995a9546461cc56b",""

I have checked all the roles in K2 workspace and all of these contain my own account and is valid so there aren't any empty roles.

I have queried the database and found that if I query K2.Server.Destqueue that there are several role names being returned there which are not actually role names. (results attached).
I want to find out how to delete these "rogue" roles as I don't think they need to be there.
 

Diagnoses

The script was looking for and deleting any roles matching K2:EU however, all the roles did not start like this.
 

Resolution

This is the reason they were still there, because the script never deleted them!
I modified the script and executed the following after backing up the entries:
DELETE FROM Oserver].rDestQueue] WHERE RName] like '%@eu.eDC].com%'

This removed them all and now there are no more errors about queues.
The workflow referenced here is also no longer on the server so there is no risk of it causing missing references.