A user is unable to open a form task to approve or reject a request. The action is blocked with an error that prevents the user from proceeding any further. The user had their name changed within Active Directory which is the likely cause.
The following error appears:
"Domain Name\User Name is unable to open worklist item"
Clearing the identity cache with a script, as well as clearing the browser cache should allow the user to open up the form task once again.