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

For me it was Avast Antivirus **!! Uninstalling it did the trick.**I don't know how is this connected to the drivers, but i got to know this when upon restart the blue "smiley screen" (which is the first screen showing any error, and disappears very fast) showed the avast .sys file name.

I had to completely uninstall the antivirus even disabling wouldn't help. 

For those who are still facing the issue uninstalling AV software may help.

I had 3 efforts without success (it gave me the errors 0xC1900101 - 0x40017), I had also problems with dism image (error 11) and some Windows Updates (database error 0x80070490). At my 4th try I found this trick of uninstalling Avast. I used Avast uninstall programme, then I enabled Windows Defender, uploaded its updates and it worked this time! It took around 4-5 hours to update from Windows 8 to Windows 8.1. Then I installed Avast again, and for now everything seems ok.

Thank you for sharing, hope it will help other users.

For me it was Avast Antivirus **!! Uninstalling it did the trick.**I don't know how is this connected to the drivers, but i got to know this when upon restart the blue "smiley screen" (which is the first screen showing any error, and disappears very fast) showed the avast .sys file name.

I had to completely uninstall the antivirus even disabling wouldn't help. 

For those who are still facing the issue uninstalling AV software may help

Yes this worked! I had the same issue but the install was successful only after I uninstalled Avast completely.  Wish I had found this answer before all the shenanigans I went through trying to upgrade to 8.1.

i think the best solution is for microsoft to send the people with registered versions on windows 8 the windows dry install disk with their own keycode for the cost of postage to resolve the problem since it seems to be their mistake and they can't seem to fix it otherwise

I read in another listing by a Microsoft support team member that there is a bug in the driver update portion of install and to give them a few days to fix it. I encountered the same error number with a dell xps15, and since I am really looking forward to this update I am hoping this si solution. hope this gives you some peace of mind

I have been trying to update since August 13. I had a hard drive failure and replaced the hard drive, installed all the operating system and other software given me by HP, everything else works but I can't upgrade to 8.1 this time. How long does it take them to fix a bug?

I have been trying to update since August 13. I had a hard drive failure and replaced the hard drive, installed all the operating system and other software given me by HP, everything else works but I can't upgrade to 8.1 this time. How long does it take them to fix a bug?

Folks, we really must be patient on this one. This thread is not yet a year old and has reached a mere 77 pages. Give MS a chance to come up with a fix.