Creo 3 sketch reference crash

[MikeMarcoux]

This occurred in Creo 3.0 M070.

A user just came to me with an error/problem I've never experience in Creo before.  He had just changed the angle of a datum that was used to create a sketch for a cut through the part.  After the change, the sketch references failed, but would not allow him to delete or replace the references.  The reference viewer buttons were all grayed out, and no matter what he did, he received a "failed references" popup.  We could not exit out of the sketch, select new references, or delete the old references.  He was essentially "stuck". We had to exit Creo completely.  Has anyone else experienced this?   

[MikeMarcoux · Accepted solution]

Figured it out.  Previous to redefining the failed sketch, there was a pop up asking if the user would like to keep the feature dependent or make it independent.  If you select dependent, references cannot be changed, essentially locking you in a state from which you cannot recover.  We recreated the error in the part, but changed it to independent.  This allowed us to pick new references and resolve the error.