In many cases it was overblown. We were forced to upgrade to Y2K compatible versions of pretty much every OS and 3rd party software we used. We also had to show that we were taking it seriously which, effectively, meant showing we were spending a lot of money on it. We spent about a week proving we weren't affected then spent about a year testing and shipping all the random upgrades. Ironically, the effect of all the change was much more risky than the original issue would have been even if we had been susceptible. On the plus side, we ended up with the latest versions of tooling etc which we didn't usually get budget for but it had nothing directly to do with Y2K.