The following is my log of upgrading an HP Stream 8 running Win 8.1 to Windows 10. I was able to download and complete the installation.

By the way, the laptop on which I am composing this email, remains at Win 8.1 Update. Maybe later.

In general, it was straightforward. One bit of good luck. The combined Windows Update messages - update installed and error code 8007068BA were confusing. After a couple quick searches, decided to not attempt to fix the error. Instead, try a restart. Fortune smiled on me. It worked - I didn't have to do more to address the error, and the installation continued. See below.

04aug15 7:00
Error(s) found.
Code 800706BA Windows Update ran into a problem."

Hope the following is interesting to some. For me, the time involved is the unknown. I took off from work to do the upgrade.

For me, my primary interest in Win 10 is Edge, PDF, and EPUB.

Good luck to all upgraders.

-o-

03aug15 - reserved under Stream 8 "Windows Update".
03aug15 - Available for download under "Windows Update".

04aug15 - Not automatically downloaded and or installed - Stream 8 turned off when not in use.
5:43 - Login as local admin, not Microsoft account, and download Win 10 2,092.5 MB.
6:34 - Download completed. "Downloading Windws 10" remains displayed above progress bar. Below progress bar, changed to "Preparing for installation". Progress bar changing.
6:57 - Progress bar complete. Continues to read "Preparing for installation".
7:00 - "The updates were installed."
More updates available. 1 optional update selected.
Review optional update.
Error(s) found.
Code 800706BA Windows Update ran into a problem."
Selected "Review optional updates" goes to "Upgrade to Windows 10 Home".
7:09 - After searching the error, and only finding Win 7 items. Decide to do nothing more than a restart, and see what happens. If not Win 10 after restart, will revisit Windows update.
Restart, and still looks like Win 8.1. Login. Goes to Windows Update.
"Windows could not search for new updates."
Selected [ Try again ].
7:13 - Windows Update, tries again.
7:14 - New dialog box. Header reads "Great, we'll get the upgrade started."
Then, "Microsoft Software License Terms"
Select [ Accept ].
7:17 - "Your upgrade is ready to install
Save your work and leave your PC plugged in and turned on. The upgrade might take awhile, but we'll let you know when it's done.
Select [ Start the upgrade now ].
7:20 - Restarts. " Configuring update for Windows 10, 0% complete".
7:30 - "100% complete", then a restart.
"Upgrading Windows 0%
Your PC will restart several times. Sit back and relax".
7:50 - "23%" ... "Copying files 80%", item 1 of 3.
7:51 - restart
7:55 - "32%" ... "Installing features and drivers 11%", item 2 of 3.
8:13 - restart
8:13 - "75% ... "Configuring settings 2%", item 3 of 3.
8:23 - "95%" ... "Configuring settings 84%", item 3 of 3.
8:25 - Screen refreshes. "Hi there, welcome back!"
Displays logged-in username.
Selected [ Next ].
8:26 - "Let's get connected"
"Pick a network and go online to finish setting up this device."
Selected a network.
"Get going fast"
Selected "Customize settings", not [ Use Express settings ].
Under "Personalization" and "Location", four defaults "On". Changed to "Off". Then [ Next ].
Under "Browser settings", accepted "Use SmartScreen..." default "On", and "Use page prediction..." default "On".
Under "Connectivity and error reporting", two defaults "On". Changed to "Off". Then [ Next ].
"New apps for the new Windows"
Selected "Let me choose my default apps".
Deselected "Photos", "Music", and "Movies and TV". Accept default "Microsoft Edge". Then [ Next ].
Completed "Customize settings".
8:41 - Login as local admin again.
"Hi
We're setting things up for you
This won't take long
Taking care of a few things"
8:44 - Windows 10 opens.
Prior settings like tile groupings do not seem to have been saved and reinstated. Or, I just don't know how to restore an equvalent view. Logout.
Login as standard user.
Prior settings like tile groupings do not seem to have been saved and reinstated.
Login under Microsoft account.
To see if prior settings in my Microsoft account will make a difference. No.

9:51 - Power down Stream 8.
a) One immediate gotcha - display locked in portrait, across all users.
Logged-in as local admin, Settings | System | Display ... "Lock rotation of this display" changed to "Off".b) On my Stream 8, 8 inch display, I'm not sure if I have a desktop mode. What do I mean?
b) Firefox and Opera run ok.
c) Previously, PDFs opened in a viewer. I did not install Adobe Reader. Now, PDFs open in Edge ... I think.
d) Redoing tiles and tile groups. Turned many live tiles off, and small. First for local admin user, then local standard user.
e) TODO Try Adobe Reader Touch from the Microsoft Store.

11:25 - Lots more to experience. Time for a break.

-o-