How was the Y2K bug solved?

Answer 1

The "Y2K bug" was nonexistent. It was a hypothetical problem that arose from complete ignorance of how computer systems work.

Another comment:

There were numerous bugs in specific programs, but none caused problems as serious as were feared in the worst-case scenarios of the day. One reason there were so few problems happening on January 1, 2000 is that companies started working on fixes as early as the 1980s. This did absolutely need to be done. Many programs were initially written at a time when (1) the year 2000 seemed ages away in the future; and (2) memory on early computers was expensive and used as efficiently as possible. Thus two-digit years were used, and in some cases a one-digit month (From January to December represented as 1234567890-&).

One very simple example of a problem that had to be prevented is how your insurance company calculates your age. If you were born in year 85, as Y2K approached you would be 98-85=13, then 99-85=14, then 00-85=negative 85. Probably some models of computers would not have been able to open files actually created a month ago (in December 1999) but appearing to be created 99 years and 11 months in the future.

It was not a nonexistent problem. It was a problem successfully dealt with by thousands of man-hours of work expediently finished.