I was using 3.5.11 for a long time, then I upgraded to 4.0.3, it installed and ran fine until I clicked on settings, Paint.net crashed; I ran repair but each time I clicked settings there was a crash. I updated .NET but still no joy. I attempted to revert to 3.5.11 but it would not install so I reinstalled 4.0.3.
When I looked through the log files I noticed a large number of entries about write permissions - so I changed the run settings to 'Run as administrator'. Result - no more crashes.
Hope this helps
