2. Go to Start>Run..., in the Open: field, type regedit and select OK
3. Click on the + sign next to HKEY_LOCAL_MACHINE to expand it
4. Click on the + sign next to SOFTWARE to expand it
5. Select the Garmin folder and delete it then exit from regedit
6. Re-install MapSource and update it to the latest version on Garmin's website.
7. Install your maps one at a time and run MapSource after each map installation to isolate which map is causing the problem.