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

@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.

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

To check system Partition: Windows Key + X, select Disk Management. All your partition are shown here.  Hope this helps and if you need further assistance post and we will be glad to Help you.

The above opinion is mine and mine alone and doesn't necessarily reflect that of Microsoft, it's employees, or any other member of this forum.

"When we try to pick out anything by itself, we find it hitched to everything else in the Universe." -John Muir

Thanks for the assistance. Windows 8 is installed on a 240g SSD in a Raid 1 with 118g free, so it is not a matter of space.

Using SFC /scannow does not find any errore.

DISM restorehealth does find errors, but unable to correct. Returns error 0x8000f081A. Google it and it returns:

0x800f081A,-2148468762,CBS_E_INVALID_DRIVER_OPERATION_KEY,the driver operations key is corrupt or invalid.

Okay, so which driver and how to fix?

Windows Update 8.1 KB2919355 tries every day, and everyday it gets to 100%, and then says it cannot complete the updates, and then undoes everything. Error is 800F0922.  A week ago the error was different (can't recall - too many other entries for history to contain); I reinstalled Nvidia video drivers and now the error is 800F0922. So far I've tried a number of solutions including use of DISM commands and Windows Update checker.  No joy.  I'm not willing to refresh the system because it means reinstalling many programs, including MS Office 2013, and besides the aggravation I'm unsure of the license implications. Don't know if MS and other vendors will allow a reactivation.  Otherwise the system has accepted all other updates, and is running fine as far as I can tell.  Also tried a manual update - again, no joy.