PS CS: Save PSD, Open PSD = File Not compatible.

The latest update to NAV appears to be the cause of the latest photoshop saving and opening problem.

We suggest removing NAV (and using something less destructive like Virex 7.2.1 if you must have virus protection) until this problem is resolved.

The error message reads: "... file is not compatible with this version of Photoshop." when opening file (Photoshop CS on Mac OS X)

For more information, see this document from Adobe:
<http://www.adobe.com/support/techdocs/331092.html>