Show thumbnail graphics in Windows Explorer Option Not Active Greyed out

SF 2008-08-26

In SW 2008 SP4 running on Vista Business 32bit
In Tools, Options, General
The option to change the status of Show thumbnail graphics inWindows Explorer is checked, but it is greyed out where we can notuncheck it.

Does anyone know of a way to change this?

We tried changing the user's permissions to full control, to noavail.

Any help would be appreciated.
Solidworks General