"Couldn't update to Windows 8.1 - 0xC1900101 - 0x40017"

I think you haven't undertood the problem, most of the people having this problem, me included, are having this issue on new hardware and free of any software and driver that could give problem...snip       

I do understand. Most of the time when I see these problems, it is on new machines that people built. Did you check all the hardware against the MS 8.0 compatibility list? Did all the hardware and drivers have the holographic tag certifying that it has passed the MS certification? Did you check the partitioning of the new drives to see if they were NTFS compliant, or, were they preformatted at the factory on a Linux based mass formatting production rig? (I can't tell you how many times I've been bitten by that.)

.

The issue is not WHAT third party software you installed. It is WHAT that software DID to the OS.

Third parry programs that modify the OS, like ones that replace the start menu, add AERO, remove the charms, removed Metro, or replace the built in security with old antivirus programs designed for other operating systems, then the resulting OS becomes a mishmash.

You are no longer running Microsoft Windows, instead, you are running Mishmash Windows.

I bought a 7" Toshiba tablet through the MS store. They sell the exact same hardware at the exact same price as the identical model from Toshiba. Microsoft calls it a Signature Edition, Which means it comes without all the shovelware that Toshiba put on the same identical tablet. I upgraded it to 8.1, the upgrade went without a hitch and was done about 3 hours after taking it out of the box.

I got the MS Signature Edition because I had purchased the exact same tablet from Toshiba two weeks earlier and spent nealy all my time with tech support trying to get it to upgrade. The first problem we found was that the shovelware antivirus had to be removed,  it prevented the Store from modifying the windows system. That got us farther into the upgrade. Then there was a helper app for the USB, a WiFi driver and a couple other things that were crashing the install, all a result of the shovelware that Toshiba installed. I didn't get the tablet from Toshiba working until a week after I had the Signature edition from MS upgraded. I did it by making a USB 8.0 install drive, doing a clean install of 8.0 from MS and then upgrading to 8.1. After all that, the upgrade went just like the Toshiba Signature Edition from the MS store.

Francesco, You are right when you say; "a big update like this should work independently of the software I've installed". That is true. However, If you have some rogue third party programs that modify the OS via registry hacks and such, or change the underlying drivers or even the disk structure, then you have a Frankenstein Zombie Alien OS,  (FZAos) and a update will not know what to do with it. The 8.1 update expects Windows 8.0, not OSX, PS3 or FZAos. Even then, only some updates will keep your existing programs, other times, you will need a transfer utility, then, you might have some programs that will need to be upgraded or are not supported.

Frankly, I am impressed that the upgrade successfully returns your system back to it's original 8.0 OS once it finds that your 8.0 copy has been zombiefied. It successfully presents you with the error message, "Can't be upgraded" and "Your OS has been restored to 8.0" but to expect it to know how your system got zombiefied is expecting the impossible. Frankly, I would not want the upgrade to be a 9 TB of download to handle every possible piece of **** the hardware vendors put on PC's . "Can't be upgraded" and "Your OS has been restored to 8.0" is pretty good compared to what most other OS's do.

Bye the way ,Francesco, I'm impressed that you managed to build a PC with all the latest stuff. I've built more than a thousand PC's for engineering firms, power plants, paper mills and othe businesses. For the most part I used tried and trusted components. If I changed to a new board, I often put it in several PC's and threw everything I could at it before I added it to my stable of components. Sometimes I spent weeks selecting something as simple as a disk controller. To build a new PC from all new versions of components takes some real skill, not to mention chutzpah.

I think you haven't undertood the problem, most of the people having this problem, me included, are having this issue on new hardware and free of any software and driver that could give problem (and by the way shouldn't be this way, a big update like this should work independently of the software I've installed). I met this problem on a desktop I assembled from scratch, with a regular copy of windows 8, and with all the newest pieces of hardware you can find on the market. I ran windows update to get the pc ready for the 8.1 update and bam, this problem came, again and again, and at the end I asked for remote assistance and they solved the problem, didn't understand how, but they did it. So they know there is this problem but they don't care, then they don't have to complain if many people use a cracked or illegal copy of windows if these is the official assistance and care

augie44, I agree with you completely.

A simple upgrade should be --- ah, simple.

Sorry, but I am a lowly common sense girl and don't know the innards of computers with all it's abbreviated CAP LETTERS and you lost me at "hello".............  (LOL to the movie)

When I see "update" I figure whoever has the update to the original knows what they are doing

and all I have to do is click.  I've never had to jump through these many hoops before.  I get

analogy of Ford/Chevy - still it is we are talking about an update to a program that they issued

in the first place.  If 8 is on there already, this is an UPDATE to 8 - not some whole newfangled

program.

"As unacceptable as it seems, it may still be the only choice. "

Actually, there is another choice. Stay with W8 and end all the frustration"

"Take your Ford to the Ford dealer, ask them to upgrade the 6 cylinder engine to a V8.  If it turns out that the Ford, had been rebuilt with a Chevy transmission, and the upgrade won't work or can't be done."

Obviously, I have failed to make my point. In the above situation, I would be told there is a transmission compatibility and they don't know how to fix it.

MS sees something incompatible during the upgrade but for some mysterious reason, won't explain it. They say there's a problem but won't say what.

That is the major compliant: There is nothing wrong with an update that fails. Stuff happens.

The issue is MS discovered a problem, but fails to tell you what it was.