Reinstalling or reconfiguring SharePoint Server 2010 can fail if you had a previous installation of SQL Server 2008 R2 PowerPivot for SharePoint. The presence of two registry keys block psconfig.exe from completing farm configuration. Follow one of the two methods below to delete the keys from the registry:

Reg File

Copy the following script and save it as a *.reg file and double click the file to merge the changes with your registry.

Windows Registry Editor Version
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\14.0\WSS\ServiceProxies]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\14.0\WSS\Services]



Open the registry editor. To do this, type regedit in the Run command.
Expand Microsoft
Expand Shared Tools
Expand Web Server Extensions
Expand 14.0
Expand WSS
Expand ServiceProxies
Right-click Microsoft.AnalysisServices.Sharepoint.Integration.MidTierServiceProxy and select Delete.
Go back a step in the hierarchy. Under WSS, expand Services
Right-click Microsoft.AnalysisServices.Sharepoint.Integration.MidTierService and select Delete.


The Error

The error occurs when you run the SharePoint Products Configuration Wizard (psconfig.exe). The wizard fails with this error, as indicated in the following screenshot.

Configuration Failed

Failed to register SharePoint services

An exception of type Microsoft.SharePoint.PostSetupConfiguration.PostSetupConfigurationTaskException was thrown.  Additional exception information: Failed to find assembly Microsoft.AnalysisServices.Sharepoint.Integration.EngineService, Microsoft.AnalysisServices.SharePoint.Integration, Version=, Culture=neutral, PublicKeyToken=89845dcd8080cc91.