CRM 2011: The specified user is either disabled or is not a member of any business unit

Check whether the system administrator account was disabled in database. If yes, enable it in database.

1. Backup the orgname_MSCRM and MSCRM_Config.
2. Find the systemuserid for system admin in systemuserbase table.
3. Find the system admin in systemuserbase and resourcebase, if isdisabled=True, set isdisabled=Flase.
4. Find the Business Unit the user belongs to in businessunitbase table. if isdisabled=True, set isdisabled=Flase. 

then Restart machine.