If you've been having trouble upgrading from Windows 8 to Windows 8.1, and are encountering Blue Screens marked 0xc1900101 - 0x40017 or 0xC1900101-0x20017, 0xC1900101-0x40019 or 0xc1900101 - 0x30018, there may be a fix for your problems. But if none of the remedies offered here get you upgraded, please head to the Microsoft Answers forum and post details about your configuration. Because after two weeks of trying, Microsoft still hasn't figured out what's causing the problem, and your input may help.
On Oct. 18 I wrote about the show-stopper bug for many people upgrading from Windows 8 to Windows 8.1. Martin Dixon posted the original description on the Microsoft Answers forum, shortly after the Windows 8.1 upgrade rolled out:
I have downloaded the Windows 8.1 update from the store but cannot get it to install. Each time I try, I get to the point where it is "getting my devices ready", then the PC restarts to a blue screen with error message. It then tries to recover the installation, fails, then restores Windows 8. When the system boots up after this, I get a message saying:
"Couldn't update to Windows 8.1
Sorry, we couldn't complete the update to Windows 8.1. We've restored your previous version of Windows to this PC.
0xC1900101 - 0x40017"
There is no explanation as to why the update couldn't be completed. Any ideas how to resolve this?
To date, almost 400 posts on that thread -- plus hundreds more on several additional, similar threads -- have led to a small handful of customer-discovered solutions, but no definitive workaround that everyone can apply.
Here are the approaches that seem to work for some people: