Error: We couldn’t complete the updates, Undoing changes. Don’t turn off your computer.

This error may appear anytime a Windows Update fails. To investigate possible solutions, we need to start with the specific error code.

We can do this by viewing your update history.

1. Swipe in from the right edge of the screen (or, if you're using a mouse, pointing to the lower-right corner of the screen and moving the mouse pointer up), and tap or click Settings.
2. Tap or click Change PC settings, and then Update and recovery.
3. Tap or click View your update history.

View failed update error code.

Please post here with your error code, so that the Community can try to help guide you appropriately.

couldn't update to windows 8.1 Error code: 0x80007002c-0x2000D

@Robert, I definitely will be doing an image backup.  One of the things I planned to do prior to the reset of the Windows Update components is to use dism to remove KB2919355 and the 5 other fixes in the standalone package.  My suspicion is that the pending install of the previously downloaded fixes is at a minimum creating confusion and making the logs harder to interpret.  

If all else fails, I have an image backup from April 10th just when KB2919355 had been offered (selectable) via Windows Update.  I hope this backup does not already contain the root cause of my install issues.

 recommendation was to run dism.exe /online /cleanup-image /scanhealth and then dism.exe /online /cleanup-image /restorehealth to minimize the number of updates that have to downloaded.

Ask about the controversy concerning plain /restorehealth versus other kinds

C.f. 

http://answers.microsoft.com/en-us/windows/forum/windows8_1-windows_update/error-0x80073712-when-installing-kb-2919355/c5a08cdf-6e41-4b67-b2ae-68f542070840?page=2&msgId=ccb118fa-34b4-4718-8489-00b3555781b6

(contains a link to Dogtamer's post about this stuff and cites an extract from it)

Also, FWIW I still think that I have seen more positive feedback about Marek Kusmierski's script (especially with the postscript) than any other procedure.  Ask about that too.

C.f.

http://answers.microsoft.com/en-us/windows/forum/windows8_1-windows_install/kb2919355-windows-81-update-fails-800f0092-and/4d4d23a3-695a-4bd4-b340-d2ce9c75919d?page=40

Also, did they mention backup so you can undo your experiments if necessary?   <eg>

failed as before. said couldn't finish the update. no error code. no anything.

I am pretty sure that files were downloaded each time.

Unless the content is changing on the host that seems absurd, especially for the big downloads.

However, for all I know this particular code might be pretty innocuous.  E.g. it could be WU saying "That's all for today." or some such.   What is a "DM" anyway?  Perhaps there is a clue back in the other codes for the same group...  Indeed:  "Download manager errors".  So it might also be a communication error or a symptom of cache corruption, etc.  Probably would be a good idea to do what Marek suggested in his postscript...

http://answers.microsoft.com/en-us/windows/forum/windows8_1-windows_install/kb2919355-windows-81-update-fails-800f0092-and/4d4d23a3-695a-4bd4-b340-d2ce9c75919d?page=40

(bottom of page, Re: SoftwareDistribution folder )