The Add-in ‘xxxx' failed to load or caused an exception in SQL Management Studio

And clicking on Yes to remove it, doesn’t help.  This is actually a permission issue from Vista and Windows 7 and up.

The service pack update to Windows Vista has been known to change permissions to the registry in a way that prevents user access to the information about installed classes: HKEY_CLASSES_ROOT. This prevents SQL Server Management Studio from loading the add-ins into the environment.

To correct this problem, it's necessary to assign permissions to the registry for the logged-in user.

1. First open the Registry Editor (regedit.exe) using the "Run As Administrator" option.
2. Right-click HKEY_CLASSES_ROOT and select "Permissions", and give the logged-in user full control.
3. The following permissions needed to be added to HKEY_CLASSES_ROOT as well:
          -Users: read
          -System: full control
          -CREATOR OWNER: full control on subkeys only