windows 8.1 upgrade fails with error code 0xc1900101-0x20017

Note that the answer accepted for this problem appears to only be applicable to systems using some form of full disk encryption.

I just tried to install windows 8.1 on my laptop, but it fails to install with the message:

Sorry we couldn't complete the update to Windows 8.1.
We restored your previous version of Windows to this PC
0xC1900101 - 0x20017

The update installed just fine on my desktop. The difference between the two machines is that the desktop has media center install, and isn't using TrueCrypt.

On the first reboot for the update, the laptop goes to the PC restore screen. Thus far I have just been selecting "Continue to windows 8."

Full WindowsUpdate.log http://pastebin.com/hGmAW4Q1

Update: Turns out it was TrueCrypt! I decrypted the drive, installed Windows 8.1, and then re-encrypted the drive and it worked just fine.

You should decrypt the HDD before doing the update. TrueCrypt is a 3rd party encryption and during setup Windows doesn't know how to handle it.

I'm concerned that the answers provided here are going to lull the original poster, and others who may read this post, into a false sense of confidence that decryption is a slam dunk solution.

It's not. My installation failed with exactly the same error code; however, I do not use encryption. Larry Magid had the same error, and he does not mention encryption. Google searches turn up a number of instances of this exact error, many of which do not involve encryption.

In my view, the evidence is clear that the upgrade package is significantly flawed, and we need Microsoft to issue an updated version that corrects this.

The best answer, in my view, to this problem is: wait a week or two. And in the meanwhile, please consider submitting a bug report to encourage them to hurry.