opm ce PipeLineManager error message

Question

A user is getting this message when trying to edit PipeLine 
 
 Any Ideas what can cause this?

Swapnil Joshi · Answer

Hi Peter, 
 Can you confirm the details of your environment? 
 Also let us know the kind of operation that you are trying to perform here along with some background. 
 Thanks | Swapnil

Peter Sande · Answer

In this case it was due to some error in attached references, Detaching references solved problem.