This release was only made available 2 weeks ago, Do you mean to say that all the companies affected by this had managed to complete full testing of this release in an environment which would not affect their live systems? Doesn't sound like it. Especially if those companies are running critical systems on ESX, then to be honest they are partly at fault. I'm sure they don't do it with Microsoft, so why with VMWare? The first rule in running systems like this is test, test, test and then test again. The testing may not have shown up the bug, but if they had spent more time on testing it, it would have shown up when the dates change.