When I was trained in computer programming starting in 1966 in College there was a term "Garbage In Garbage Out"

 In other words if your operating system is corrupt you are only going to get garbage to come out of the computer system.

So, when they downloaded the wrong file into the operating system it all was corrupted by one bad file. 

So, this is why most Air traffic was shut down nationwide for part of Today and it also affected Canadian Air Traffic too.