When attempting to update your CRM 2011 Server to CRM 2011 Rollup 4 or 5, you receive an error message “Generic Error” upon reboot. After reviewing event logs you see an error stating “Method Not found: Void. Microsoft.Xrm.XXXXX”.

The fix is to use the GACUTIL for the .NET 4.0 framework and re-register 2 dlls from the CRM\Bin directory on the CRM server.

From a command prompt, go to:

C:\Program Files\Microsoft SDKs\Windows\v7.1\Bin\NETFX 4.0 Tools

gacutil /i “C:\Program Files\Microsoft Dynamics CRM\CRMWeb\bin\Microsoft.Xrm.Sdk.dll”

This will register the missing .DLL. Finally issue an IIS reset and start using your CRM Again. You can download the Windows 7 .NET Framework 4.0 Gacutil (Windows 2008 as well) from this link:

http://www.microsoft.com/download/en/confirmation.aspx?id=8279