You may receive the following error message when attempting to deactivate/activate or remove a user account from the Dashboard:
An unknown error prevented the wizard from retrieving the user account information. If this problem persists, restart the server, and then try again.
The dashboard log file will contain the following error:
 110421.133002.7958: IDENTITY: ErrorCode:2221 UserErrorCode:Failed BaseException: Microsoft.WindowsServerSolutions.Users.UserException: SetUserStatus at Microsoft.WindowsServerSolutions.Users.User.SetUserStatus(UserStatus value) at Microsoft.WindowsServerSolutions.Identity.UI.AddinPage.<.cctor>b__8(User a)
You may also experience a problem where the user account unexpectedly disappears from the Dashboard list of users. The account is still listed in Active Directory and still a valid account but it is not displayed in the dashboard.
The issue can occur if the user's logon name does not match the account name. This can happen if users are created using native Active Directory Users and Computers management console, or if users are migrated over from an older version of a Windows Server operating system. This will not happen if users are created using the SBS 2011 Essentials dashboard. The accounts that are created with the Dashboard tools are always created in such a way that the logon name matches the account name. In a migration scenario, the logon name may not match the account name. You can import the account into the dashboard using the import-wssuser PowerShell cmdlet but if the names don't match you won't be able to deactivate or delete the account and after a period of time, the account may disappear from the dashboard.
Here is an example of an account that will experience the problem.
In this case, the account Don Funk has a logon name of donfunk.
If we examine Active Directory we see this:
The account name is Don Funk (notice the space between Don and Funk). This extra space is the cause of the issue. The name of the account must match the logon name.
The issue is resolved by SBS 2011 Essentials Update Rollup 1. For information on Windows Small Business Server 2011 Essentials UR1 please refer to the following Microsoft Knowledge Base Article http://support.microsoft.com/kb/2554629
Note: The Update Rollup does not correct accounts that were imported prior to the rollup installation. It is possible for the account to disappear one more time after the rollup has been installed. If the account gets removed from the Dashboard after UR1 is installed, you can use the following steps to import the account back into the dashboard. Once the account has been imported with Update Rollup 1 installed, it will no longer disappear.
1. Open a Command Prompt window as an administrator.
2. Change directory to c:\program files\windows server\bin
3. Type wsspowershell.exe, and then press ENTER.
4. Type import-wssuser –name <username>, and then press ENTER.