This was back in the day when all installation programs came on 3.5" floppy disks (sometimes, a lot of floppies). Some of the makers of those programs didn't bother to make the floppies read-only after loading the installation program.
Sure enough, the idiot had used a few of those disks for file storage. It wasn't so bad that he had screwed up a couple of Windows 3.11 disks, as a couple of those were available. But he had done that to at least one CAD program disk and he was the only one in the company with that program. I don't remember how much it cost him to get a replacement, but he was crying about it for a long time.
His boss took great pleasure in telling him that the company wouldn't pay for it, so either he had to or it was back to the good old drawing board.
Good times.