Here's a repeatable issue (both in 5.0 and 5.1):
Take a Personal Lectionary and Prioritize it so that it shows up on the Home Screen.
Then try to re-compile the PB. It crashes with this error:
[Info] Starting build for PBB:a241bb92cf2645558c9f5cc3844cba55
[Error] Error while building book: Could not remove existing resource. Please close all other open panels and try again.
[Error] Exception: LDLS4.Panels.PersonalBookBuilderPanel.PersonalBookBuilderException: Could not remove existing resource. Please close all other open panels and try again.
at LDLS4.Panels.PersonalBookBuilderPanel.PersonalBookConverter.<CreatePersonalBookWork>d__c.MoveNext()
at Libronix.Utility.Threading.AsyncWorkerTask`1.EnumMoveNext()
at Libronix.Utility.Threading.AsyncWorkerTask`1.EnumMoveNextWithCatch()
at LDLS4.Panels.PersonalBookBuilderPanel.PersonalBookViewModel.<CreatePersonalBookWork>d__a.MoveNext()
If you re-prioritize the PB so that it no longer is top priority, then the book compiles without errors.
1803.Logos.log