So , I had this SharePoint Feature as part of PowerPivot install that went completely rogue on me. The feature wasn’t part of my SharePoint Farm Solutions, but when I do a Get-SPFeature it would show up on the list of items.
The following error would show up , when I tried to add the solution.
The ugly truth was the feature didn’t get removed properly no matter all the Uninstall-SPfeature and “Force” this and that.
The feature was sitting within my config database and wouldn’t remove itself.
The trick was to use
stsadm.exe -o deleteconfigurationobject –id “FeatureID”