Cumulative Update KB3200970 Windows 10 version 1607 build 14393.447

Most costly update. This update costed me 563.04 MB of my internet data .

Its weird, that's for sure. Still on 77% after 1 hour 50 minutes. The HDD light is doing little flurries of activity so I'll leave it a bit longer.

Recent updates have become traumatic and extremely time consuming. If I didn't actually like 10 so much then I wouldn't hesitate in going back to W8.1 and perhaps just update infrequently (i.e. turn off WU).

Another nugget of useless info... the only times I have needed to recover from a disk image have been because of WU issues.

Mine was fairly quick to download, but it took ages to install.
Everything seems to be running smoothly.
I must do an image backup soon!

I powered down with it still on 77% after 2 hours of sitting there. Left it for an hour and now rebooted. Immediately its now showing 90%. I'll leave it some more.

I wonder whether this odd behaviour has anything to do with the 'quick start' files. I've noticed that restored disk images immediately install updates pretty quickly and correctly. In use images (i.e. the system as it stands in everyday use) appear to have the issues.

On my desktop it downloaded rather quick. On my Acer Aspire V5 it took about 25 minutes. I still have another desktop, two laptops and a tablet to update. I'll do them later.

4 hours after beginning and I now have my 32 bit system updated. It seems it had stalled at that 77% point and shutting down and restarting let it pick up again. Installed very quickly from that point onward.

Its all so random as to what is going to happen. You just don't know from one update to the next how it will go.

Mooly said:

...I wonder whether this odd behaviour has anything to do with the 'quick start' files..

Possibly. I have quick start turned off and my updates download and install relatively smoothly. Another factor may be that after each update I use Disk Clean Up to clean up the system files, including the Update Files. The only one I ever had problems with was KB3189866, but almost everyone did with that one. Got it OK in the end by rebooting when it was stuck at 90% for half a day - carried on from where it left off and finished some 20 mins later.

Took a while on my ancient Dell Dimension, but went through smooth. On my wife's brand new Surface Pro 4 it got stuck at 95% probably for an hour, and the machine got really warm! That's when I decided to give it a restart. Update picked it up and finished it off this time around fairly quickly.