KB3000850 fails to install with error code 800F0922

I'm hoping someone might be able to assist. Update gets to 99% and then rolls back. All other updates have completed without issue.

Win8.1, x64

Tried msconfig disabling all non-Windows components, no change.
Not running any sort of secure boot (desktop machine), not running Bitlocker.

As admin:
ran DISM /Online /Cleanup-image /RestoreHealth
ran sfc /scannow (no issues detected). CBSlog.txt file here: Microsoft services

Research on 800F0922 says that if might be caused by the GPT/EFI partition being full. It is 100MB and only 30% used and there are no disk full errors in my CBS. The MSR is 128MB (the disk is GPT). So I don't think this is the issue. Also, I do not have a Cisco VPN as that is said to be another cause of 800F0922.

Does anyone know how I might solve this?

That update has been known to cause issues in the past. Do a system restore to a time before you installed it.

Ok tried that. Same result. Thanks anyways.

Actually, I would try running sfc /scannow again. When you ran the first time it may have timed itself out for some reason. Sometimes it can take more than running it a single time to correct all file irregularities. When it is finished it should message with either No violations found, Repaired all problems or repaired some problems but could not repair all. If the latter is the case you should run Dism /Online /Cleanup-Image /RestoreHealth restart and run sfc /scannow again. Remember, run all these with Adm. Privileges

The situation seemed hopeless until I found this: https://www.winhelp.us/non-destructive-reinstall-of-windows-8-and-8-1.html

I re-installed the OS, all updates applied successfully, and my PC was 98% unchanged, a few tweaks to get it back to the way I like it. Didn't have to reinstall all my apps, etc. This was a great find. Plus, I didn't even have to go through Windows activation, my PC stayed activated (as it should).

I have been delaying this update for ages after reading all the negative comments on it's installation and the problems and error messages associated with it.

Finally bit the bullet this afternoon and had a crack at installing it after doing the mandatory image of the boot drive first.
Much to my surprise the whole process was quite painless and everything seems to worked well.
Have not noticed any issues arising after Windows restarted

I wonder if the people having problems have originality had win 8.0 systems upgraded to 8.1 rather than doing a clean 8.1 setup from the start.

EDIT:
Forgot to mention that I also have Avast antivirus installed and still did not have any problems, so I think that issue has been satisfactorily resolved now.