Hi Colin. You've already checked what I would have suggested. I've not come across this problem before. The way I see it you have 2 options. Do a Reinstall of CFS2 (NOT Uninstall/Install). This will restore all the default files but you won't lose your addons unless they're modified defaults. You will have to reactivate your 3rd party scenery. Check out my CFS2 FAQ page here for details. http://www.simviation.com/lair/cfs2faq.htm

If you have enough spare HD space the alternative is to do a duplicate install of CFS2. Simply rename the CFS2 root directory folder to any other name. Then insert the CD & install to the default path in the usual way. You will then have 2 separate installs of CFS2 that will run independently. The latest install will be the master & the MB should read this one. If you wish you could transfer all your addons to the new one. It's then quite safe to delete what's left of the original.

That's great Colin. Glad one of my suggestions worked anyway. Thanks for the feedback.