First time I've heard of it on any OS, actually. Then again, I'm at the lower end of IT literacy compared to a lot of the folk here, never having been a sysadmin on anything other than mainframes umpty years ago, I've missed the joys of having to handle mass upgrades of any kind of boxen, whether 'nix or Windows. And my personal Windows 'upgrades' were only ever clean installs, whilst I've had a Linux upgrade bork things precisely once - and even then it didn't stop me using my PC, it just didn't complete the upgrade and left a few programs trying to use incompatible library versions. Clean install of the new version leaving the home directory alone whilst I was drinking a cuppa sorted it.
<joke>In short - if a bunch of commie-loving pirates can get their cancerous virus of an operating system so right, then why can't the dear little angels with so much wonderful expertise at Microsoft who work so tirelessly to bring sweetness and light into our lives get it anything like as right?</joke>