There Was An Unhandled Exception Trying To Save Your Rom To Disk -

Immediately back up your critical files (including ROMs and saves). Then run a diagnostic tool like CrystalDiskInfo (free). If it shows "Caution" or "Bad," replace your drive.

It sounds simple, but if your hard drive is full, the "unhandled exception" will trigger. Immediately back up your critical files (including ROMs

This error frequently occurs if you moved your ROMs from an old hard drive, a USB stick, or another user’s folder. Windows applies "inherited permissions" that may block write access. a USB stick