After installing windows update my NAS not working? I am pretty sure it happened after installing the windows update patch in Jan 2014. I have narrowed it down to the security update KB286330 If you have mapped the drive say to M: previously, the NAS drive will still be there, however if you open the File Explorer and click on Network, the NAS drive will not show up. The patch only affects Windows 7 but I do have the same problem with my new Windows 8 notebook PC as well. The problem, after a lengthy investigation, seems to be related to Firewall setting. In my case, it was the Zonealarm firewall settings.
You can still install the KB286330 patch, but need to change the public zone from high to medium resolved the NAS issue. alternatively you can still set the public zone to high but add the NAS ip address to the trusted zone (see picture).
How to uninstall a botched security update?
Go to “Review your update history” -> Installed Update -> look for KB266330 (or use the search bar) -> right click “Uninstall”