Problem:  I encountered a problem while restoring a Microsoft Exchange server to a different server.  After restoring the majority of mailboxes, one restore failed with an access denied error.  When I tried to re-run the job I noticed the resource credentials list was now empty and the options were all greyed out for changing, clearing and testing the credentials.

Resoultion:  http://www.symantec.com/business/support/index?page=content&id=TECH125604