Before the Hotfix I was getting a very occasional freeze. I therefore installed the Hotfix. Now I am getting a CTD on every flight. I really need the better tweaked version when it is availble. Thanks for taking notice of user's comments.

There is a post (now well buried) that indicates removing the PMDG DLL's from the [Trusted] section of FSX.CFG fixes this - just remove them all and they will be rebuild as required. Seems you end up with muliple extries for the same DLL due to DLL being updated in hotfix...

thanks Husker, I'll give it a try.