Our primary update server is down for some reason, we don't know why as of yet (and normally this wouldn't be a big deal), but the bigger issue is this:

For some reason, the regular Windows updater is failing to fall back to the secondary update servers.

As of yet, we don't know why this is not working right on Windows. It appears that only Win32 is affected: Mac, Linux and Win8/WinRT are all fine.

To immediately work around the issue, we've made some changes to the actual DNS entries to cause the "secondary" servers to be primary for now. However, the "TTL" or "Time To Live" on the DNS record is 3600 seconds, or one hour. Meaning that some upstream nameservers and OS resolver libraries could take as long as an hour before they'll consider checking to see if there's an updated version of the record. (Ie, it could take an hour to stop being a problem, for some people).

You may be able to accelerate the process by going into Control Panel, Administrative Tools, Services, and then finding "DNS Client", right-clicking and selecting "restart". That made it work again on my Windows 7 machine.

Hrm, working fine for me as of 7:45 PM CST.

Win XP 32

Yes, it's running the secondary update server now as update1.

There's a workaround a sysadmin could be proud of. :)

FYI that the primary has been back up since yesterday, and I swung DNS back over to it last night.

Additionally, the Windows updater has been patched to correct the fallback bug.