> For some reason the webserver serving virus definition files to all endpoints started serving malformed virus definition files, sometimes they were all blank

> For some reason the webserver serving virus definition files to all endpoints started serving malformed virus definition files, sometimes they were all blank or filled with random bytes That sounds like some virus protection on the server was stopping the reads from disk, and instead of throwing an error it was providing 0's for the output data instead. It'll be funny if there's actually some antivirus package that caused it. ;)