What a bummer. I get 3/4 of the way through, it reboots to my unlock screen and nothing happens so I assume it's done. I swipe to the main page and it's exactly the same. The download didn't take and it's apparently NOT resumable. So now I have to wait another 15 hours or so to check again for the upgrade I already had. Damn.
Well, this sucks. I started the download again. It rebooted. I go downstairs to take out the trash and get back to a message "update could not be complete". End of story. No reason. No nothing. Now I have to wait another 22 hours to check for updates again. What a joke.
Sounds like a wake lock issue. Download GSam Battery to verify that. In the meantime, you could download & activate Wake Lock PowerManager and then reattempt your update, or simply turn off Wi-Fi and download it via your data.