A strange one this - but I'm sure this is the second time we've seen the problem. As I can find no other articles anywhere else on the internet about this particular issue I thought I'd write this post.
We took delivery of a new Dell PowerEdge T110v2 very recently and started setting it up for a new customer. One of the first things we do after quality-checking the server is to power it up and get the operating system bang up to date by running Windows Update continually until there are no further updates to install.
On this server however, updates got stuck - hanging at 0% on every occasion. I think I managed to get one optional update installed but still the other updates simply would not download or install - still hanging at 0%.
So after a few hours of trying different things, we wiped the server hard disk and completely reinstalled the operating system, expecting that this would improve matters - it didn't.
By midnight, we tried one more thing - we set Windows Update to Automatically Download and Install Updates and then left site hoping that the server would have managed to do some background updates by the morning.
When we got back to the server the next day, it had already installed some of the updates and we were then able to manually install the remaining updates on the server.
So - if you are having the same problem on a Windows Server 2012 - then do yourself a favour - set updates to automatically download and install and then just wait until it's done this at least once. I hope you'll find subsequent updates can be run manually.