When was the Y2K problem discovered?
The minute a programmer decided to use only two digits to represent years, the Y2K problem appeared. For a competent programmer, he/she probably realized the deficiencies (it won’t work after/on year 2000), but most programmers let it go because it was unlikely the program would still exist and be run for such a long time. As year 2000 approached and companies realized that people were still running these programs, the Y2K issue really became a problem, and the programmers had to go back and patch/update their old software. So in general, there isn’t a “date of discovery”; we knew about it but didn’t think it would be problemsome until later. Then the media kind of blew it out of proportion.