Cannot find required source files

I have changed the location of the source files for SW2012 SP4. I want to repair my SW2012 SP4 installation (after SW2013 beta messing things up). So I go into the Installation Manager, Modify the location (by changing the selected products slightly to get the new location to 'stick') and go ahead and it still says 'cannot find required source files'.

Why is this still so difficult to change? I assume I have to uninstall and reinstall completely or does somebody out there have a trick to this?

Any help would be appreciated.

Thanks.

Gary

SolidworksAdministration