My S3D version 5.0.1 is also continuously crashing during start after upgrade from 5.0.0 (64bits version). The previously version (5.0.0) was running fine, no single instability. I've already uninstalled both version 5.0.0 and 5.0.1 and deleted all files under C:\Users\%user%\AppData\Local\Simplify3...