I've been trying to install Exchange 2007 SP3 on our server that is currently running Exchange 2007 SP2, but on every attempt I get the message "unexpected error 0x731ADF33" at the point of "PreSetup". This is right after the Readiness check completes successfully. Here are the details of the server: Windows 2008 Standard with SP2 Exchange 2007 SP2 with Update Rollups 1,2,3, & 4 (No Interim updates installed) All Backup Exec and McAfee services were stopped prior to attempting the upgrade. The PowerShell execution policy was set to "Unrestricted" prior to attempting the upgrade. The domain administrator account which has the Exchange Organization Administrator Role was used in attempting the upgrade. Here is the portion of the Exchangesetup.log that relates to the error message: [11/20/2010 10:14:09 PM] [1] [WARNING] An unexpected error has occurred and debug information is being generated: Unexpected error [0x731ADF33] while executing command '$error.Clear(); $RoleNames = $RoleRoles.Replace('Role','').Split(','); if( test-path "$env:TMP\StoppedServices.xml" ) { .\ServiceControl.ps1 Stop $RoleNames; } else { .\ServiceControl.ps1 Save; .\ServiceControl.ps1 Stop $RoleNames; .\ServiceControl.ps1 DisableServices $RoleNames; }'. [11/20/2010 10:14:09 PM] [1] [ERROR] Unexpected error [0x731ADF33] while executing command '$error.Clear(); $RoleNames = $RoleRoles.Replace('Role','').Split(','); if( test-path "$env:TMP\StoppedServices.xml" ) { .\ServiceControl.ps1 Stop $RoleNames; } else { .\ServiceControl.ps1 Save; .\ServiceControl.ps1 Stop $RoleNames; .\ServiceControl.ps1 DisableServices $RoleNames; }'. [11/20/2010 10:14:09 PM] [1] [ERROR] File F:\Exchange2007_SP3\Setup\ServerRoles\Common\servicecontrol.ps1 cannot be loaded because you have elected to not run this software now. [11/20/2010 10:14:09 PM] [1] [ERROR] File F:\Exchange2007_SP3\Setup\ServerRoles\Common\servicecontrol.ps1 cannot be loaded because you have elected to not run this software now. [11/21/2010 7:39:41 AM] [0] End of Setup [11/21/2010 7:39:41 AM] [0] ********************************************** Would appreciate any help\suggestions you guys can offer. Thanks. Atman

I have googled for the error message "unexpected error [0x731ADF33]" but found nothing.

Just in case anyone is interested in knowing the solution to the problem, I had to uninstall the update rollups in order to successfully install SP3. Even though Microsoft says it is only necessary to uninstall "Interim updates", it so happens that it is sometimes necessary to uninstall the rollups as well. Atman