ULS error: Could not load file or assembly 'Microsoft.AnalysisServices.SPAddin"

After uninstalling PowerPivot, the error below keep popping up in ULS log.

Event manager error: Could not load file or assembly 'Microsoft.AnalysisServices.SPAddin, Version=12.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91' or one of its dependencies. The system cannot find the file specified.

My first thought is that there are some obsoleted features not getting uninstalled properly. That turns out correct. I removed the two features below through PowerShell script here.

e8389ec7-70fd-4179-a1c4-6fcb4342d7a0 ReportServer
1a33a234-b4a4-4fc6--96c2-8bdb56388bd5 PowerPivot Feature Integration for Site Collections

However, the error message is still there.

After quite a while trouble shooting, I finally found the problem: it is caused by obsoleted event handlers. They are supposed to be uninstalled with those features, but for unknown reason they are still there.

So, again, I removed them through PowerShell


Assembly: 'Microsoft.AnalysisServices.SPAddin, Version=12.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91', Class: Microsoft.AnalysisServices.SPAddin.ReportGallery.ReportGalleryEventHandler, Type: ItemUpdated

Assembly: 'Microsoft.AnalysisServices.SPAddin, Version=12.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91', Class: Microsoft.AnalysisServices.SPAddin.ReportGallery.ReportGalleryEventHandler, Type: ItemAdded


Finally, the SharePoint farm back to peace.