As the title say! On one of my computers, I got the problem with updating to 14379! 3 times the upgrade went : to 72%, resulting in the return to 14376 to 94%, also resulting in return 14376 to finish and come to the log on screen, resulting again in going back to 14376 on the forth, all went ok! Now the computer is running on 14379 with no problems. Every time I was looking for the Log File, it didn't exist! The only message was on screen before returning to old install, that there was a problem and the former build was a need to be recovered. I didn't use to do anything else as just to switch on the computer and switch off before leaving office, just to see what will happen. After the recovery to 14376, I couldn't manually start the upgrading because the upgrade was not shown in Settings/Update! Even run a re-check, it didn't appear! As I didn't have the time to something else, I left the machine just powered On while in office. Normally I didn't be in Office on Sunday's, just was need to be yesterday because of a problem on of my Backup Device not to be working (1 tape was 'hanging') and just as I was going to Off the power in Office, that computer started to Auto-Upgrade again, so I was leave the power On and running over the night. Just to mention, every time the Upgrade file (ESD) were downloaded again. Luckily, that computer is just one of the spares, and normally not be used every day! As for the install, everything is as it is on all our Office Computers. Any data are auto saved on our Data-Fileserver, from wich the Auto-Backup is running to BD and Tape. The Tape system I use is Quantum SuperLoader 3, LTO-5, 16 Slots, 6Gb/s SAS, a 2U Rackmount Autoloader, using 3TB LTO Ultrium5 Tapes. The software used is Yosemite Server Backup for both: BD and Quantum Autoloader (Windows and Linux Server). All Data are not kept on the Workstation Computers, it's saved on Server only, and that applies also for the Computers used by my Staff! Data-Security has the highest priority in my company! Everything is backed up 3 times: on RAID on BD 50GB Media on Tape I also have 3 Stand-By Computers in Office (and 1 at Home) with same OS and Software (all activated), so, one goes down, isn't any problem. As such is expensive, it's not really useful for Home use! OK, next time such will happen, I'll simply wait for MS to correct and not to invest any time to search the culprit, which isn't shown by MS! The MS Feedback, to which I reported as well, didn't gave a single answer, means is simply useless!