This error message typically appears in emulation software (such as Dolphin Emulator, Cemu, or various NES/SNES emulators) when the program attempts to create a save file but is blocked by the operating system.
"THERE WAS AN UNHANDLED EXCEPTION TRYING TO SAVE YOUR ROM TO DISK."
Pre-patched ROMs (like those with Anti-Piracy patches) can sometimes cause conflicts. It is usually safer to randomize a clean ROM first and then apply any necessary patches later.
A dialogue box bloomed across the center of the screen, its borders jagged and pulsing: