I have no idea whether this particular failure was Microsoft's fault, but I was in the air on September 14, 2004 when a substantial portion of the southwestern US's air traffic control went down:

https://spectrum.ieee.org/lost-radio-contact-leaves-pilots-o...

(I was near ORD at the time, flying toward the outage area. We diverted to ORD, and the pilot was very friendly about it.)

At the time I thought it was Microsoft's fault, as Windows 95 and 98 were susceptible to crashing when GetTickCount() overflowed, and this ATC crash was due to a 32-bit millisecond counter on a Windows machine overflowing, but in this particular instance the system was apparently not running on a version of Windows with this particular bug and the failure was just an application error.

Aren't computers great? :)