For two hours, she compared byte-for-byte. She traced the assembly instructions. She found it at offset 0x1A3F : a single byte changed from 7F (instruction: JG - Jump if Greater) to 7E (instruction: JLE - Jump if Less or Equal).

“It’s blaming eutil.dll , Mira. Should I replace it from the backup?”

It was a cosmic ray, a random quantum hiccup. But in the world of DLLs, it was a stroke.