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

will actually give you the error number, which isn't all that helpful, but at least you'll

know the error number.

Typically what you see then is just a summary error code--insufficient detail to even formulate a hypothesis about what is wrong or what you should try.  You need to dig out the logs.  If the failure is during an update the ReportingEvents.log can at least give you a timestamp range to consider and some context for further investigation.  Then, the next general place to look would be the CBS.log (or archived piece of it) which corresponds to the details that you are searching for.

Good luck

Robert

I tried to contact them via mail or chat, nobody is answering me

Good luck with that.  I called and was "escalated" not once but twice to someone supposedly

really high up on the "help" chain.  Was on the phone with him tweaking this and that for a

couple hours, started the update while he was on the phone, then he called me back.  Boy,

was I feeling confident help was on its' way.

Ended up I did the update with him and tweaking several times until he said what will solve

my problem is a clean disc for the update - he would send it to me.  Don't touch the new

computer until it got there and start fresh with putting it in.  Did that.  Same error.

That's what led me here and I did update on Drivers and took out my Anti-Virus complete.

Then, and only then, did it work. 

You would think MSN would figure that one out and tell somebody.  Also others are still

having trouble even though they deleted their Anti-Virus (which makes the computer

vulnerable, until you put it back).  Why would they make an update that will not run

with anybody's anti-virus?  Why not an update that checks to make sure all the Drivers

are updated and tell you which ones need it FIRST?

Wonder what the next update will bring - and should we even bother to update?

There is more to it than that.  It happens really fast and then is gone - but before that it

will actually give you the error number, which isn't all that helpful, but at least you'll

know the error number.

What I mean is that it comes up fast on the screen, then disappears and you can't get it

back again, then later it says "an error has occurred".  Most of the time it is the error

that is imbedded in the Topic of this thread.

I know, who wants to continually watch the screen for the couple hours it takes to update -

looks good - restarts - and then the error!!

 I want somebody paid by Microsoft to help me

http://windows.microsoft.com/en-us/windows/support#1TC=windows-8