When deleting a mailbox from Microsoft Exchange Server, the following error is sometimes displayed, especially if the user has been an Exchange Administrator:
Microsoft Exchange Error - Action Remove could not be performed on object 'User' Error: Active Directory operation Failed on User. This error is not retriable. Additional inFormation: Access is denied. Active directory response: 00000005: SecErr: , problem 4003 (INSUFF_ACCESS_RIGHTS), data O The user has insuFFicient access rights.
Open Active Directory Users and Computers
Open the user to be deleted
In the Security tab, give ‘Exchange Servers’ full control
Then, delete the mailbox with the Exchange Management Console or Shell
This article was originally posted at the Tritone Consultants Website