Symptoms

A Cannot Update error received when trying to update/publish a marksheet that complains about Violation of PRIMARY KEY constraint 'PK_tblCumilativeGradesDetails'. Cannot insert duplicate key in object 'dbo.tblCumilativeGradesDetails'

Resolution

To resolve this issue. Undo the marksheet update. But since you don't have access to the undo update button on the marksheet.  Use the undo update button on the list window. Click list button and scroll across to see undo buttons 

Cause

This error means the grades you are trying to publish are already posted to the report card. Either because someone else published them via remote app or a previous update/publish ended prematurely.