I let the battery on my Microsoft Surface 2 run out and left it without a charge for maybe a week. When I booted it up again, Windows 8 thought 40 689 days had passed.
I have no idea how this could have happen. Interestingly, the clock was correct to the second. It was only the date that was off.
This caused things like the network time-server synchronization protocol (NTP), HTTPS, Windows Update, App Store, and many other system services to fail completely. You can see from the screenshot that even the Windows calendar gives up past the year 2099.
My Windows login is tied to a Microsoft Account. Luckily, it did not decide to lock me out of the system. A Windows account and the Microsoft Account usually checks up on each other on a was up to date.
NTP not working prevented the problem from correcting itself. NTP will usually disregard any timestamp sent from a time-server that is implausible out of sync with the system’s local time. I have always thought of this as a security/sanity feature, but now I am not so sure anymore.
Some other smaller problems could be seen in Windows Update. The timestamp for the last time it had checked for or installed any updates were set to “Never”. After having manually corrected the time, I had to fiddle around in the system registry to clean out scheduled system maintenance tasks that would next run 111 years in the future.
The Maya calendar ended in 2012. The Windows 8 calendar seem to end in 2099. It sounds like a good time to predict the next coming Apocalypse.