Windows 10 Insider Preview Build 15042 for PC & Build 15043 for Mobile Insider

Insider build 15042 fell over At the 3rd restart, 1st time that has happened.
Took two reboots to get it to revert to previous build, first reboot brought it back to the stalled state.
I gave it anther go. 08:48
Insider update very slow this time, sat at 99% downloaded for several minutes, and has taken longer over 'preparing to install' sat at 90% for several minutes. Restart Now. Here we go 09:03
Configuring update 100% complete 09:07
Same result, seems to have stalled at 3rd reboot. 09:23
I'll let it sit for longer this time to see if it eventually progresses.
After the reboot that occurs at 75% complete the system get to showing the Windows logo, and the throbber starts, then stalls with 5 dots showing on the left of the usual circling position. No apparent disk activity.
Now 09:45. still stalled. About to reboot.

Pretty smooth for me. When I first started 15031, went to softwaredistribution/downloads and there were about 8-10 files already there, dated 2/24. Went to check for updates and it started download. I counted 4 restarts and ended up @ 42minutes. UUP was on. Used Macrium for first image.

Finally got the build installed through an ISO I made of the UUP files I had to obtain from another source because I never could get the UUP download to finish--it stalled shortly after beginning to download updates in the preinstall phase of the upgrade. I mentioned in earlier posts that, this time, the UUP-off registry hack failed to work, and that was true throughout the day. With UUP off I consistently saw "No updates available" no matter what "stimulus" I tried. Soon as I turned UUP back on, however, and tried again--the downloading began immediately--but then stopped shortly thereafter, never to resume--Well, I let it ride one hour while attending to something else and when I came back it had not budged--so, that was that.

As it was, even with the uup-derived iso, the first attempt failed at ~70%. I then followed Microsoft's instructions in the "known issues" sections relative to a "small number of systems" (ha!), initiated the second iso install attempt which, I am glad to say, succeeded! I'd like Microsoft to worry far less about "delivery" methods and much more about getting these builds into the hands of Insiders so that we could actually beta-test them--instead of beta-testing WU delivery schemes. Microsoft could do this very simply by putting the iso's for each build on the Win10 Insider's site. Provided them feedback about this, today, but somehow I don't think it's going to amount to much...

Don't know why, but at no time since Microsoft began UUP service has UUP enabled me to install a build! It has failed every time. The one time I thought it had worked I looked afterwards and discovered that I had turned UUP off prior to the install attempt and simply forgotten about it. UUP is obviously working for some people, but I think it's interesting that it has *never* worked for me.

Ran Brink's Reset_Reregister_Windows_Update_Components.bat, rebooted
Build 15042 went through the 'preparing' phase, but crashed before it got to the first installation restart. Restored previous version. Suggestions, please

A new Cortana animation, a "flash disabled" pop-up notification and some "fixes", most user will never notice...but still no options to customize the system font or app fonts e.g. nor a fix for the blurry W95 style settings windows, like the device-manager, or the event-viewer...
Ridiculous.