Every now and then, especialy with new installations Windows server 2012 and 2012 R2 get stuck in a reboot loop. After initial installation a massive batch of patches is retrieved and installed. On reboot, a failure message is displayed and windows tries to undo the updates. After a lengthy period of time the server reboots, and the process repeats.
Usualy if you leave this process alone, the server will come up after a few cycles (which can take more then an hour). However, on the next patch installation the entire process repeats.
All the usual option of resetting Windows update and clearing caches wont solve your problem. The below brute force method will break the reboot loop. After that try to install the packages one by one to determine the cullprit for further investigation or hiding.
- Boot from recovery dvd or usb
- Choose “repair computer”
- Enter the command prompt
- delete c:\windows\winsxs\pending.xml