I am getting an error during the compatibility check when installing or upgrade windows 2008 64bit enterpricse server to windows 2008 R2 enterprise server.The Error is appears after I select Download Updates, I select the OS version "Windows 2008 R2 enterprise (Full installation) x64", I OK the License Agreement,I Select Upgrade.The compatibility check starts and I get an ERROR Box: "Windows Installation encounter an unknown error and cannot continue" With OK selection only.I do not get errors in the event viewer or any other indication of with the problem is.

You might give this a go.Microsoft Assessment and Planning Toolkithttp://www.microsoft.com/downloads/details.aspx?FamilyID=67240b76-3148-4e49-943d-4d9ea7f77730&DisplayLang=enRegards, Dave Patrick .... Microsoft Certified Professional Microsoft MVP [Windows]