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.
I'm using WinMagic SecureDoc (6.1 x64) and my update failed as well with the same error.
This may be indeed something connected to encryption.
As Win 8.1 is supposed to have a built-in auto-encryption there may be some conflict...
Yepp, it is the encryption indeed. Not TrueCrypt only. BitLocker and I think that any kind of an encryption sw will cause this. It does not really matter whether the sw is or is not compatible with Windows 8.1. The 8.1 update runs fine after the HD is decrypted.
There is no choice, you must decrypt the drive before the upgrade.
Yes Just Decrypt the Disk or Volume! I used PGP and after decryption updated fine!
I just bought Windows 8, which I downloaded to my PC. The PC has full drive encryption, and I selected "Keep nothing" type of install for Windows 8.
When the downloader finished and restarted the computer, I was again prompted for by TrueCrypt password (which is accepted) and a few seconds later, saw the "Something went wrong" message in the installer.
The computer rebooted, and now it claims my TrueCrypt password is wrong. Wtf do I do now?
PS. I backed up everything and don't have a TrueCrypt rescue disk.
Windows 8 has several new features incompatible with Truecrypt - the feature called Secure Boot, mainly; and possibly Windows 8's new hybrid boot. Therefore, full system drive encryption is not supported by Truecrypt (http://www.truecrypt.org/docs/sys-encryption-supported-os).
With Windows 8 Secure Boot enabled (by default on supported hardware) Truecrypt will never work (the point of Secure Boot is to prevent bootloader modification or "hijacking"). Check if you have Secure Boot enable first (http://www.eightforums.com/tutorials/20208-secure-boot-confirm-enabled-disabled-windows-8-a.html).
I would consider using Windows 8 Bitlocker encryption in place of Truecrypt at this time as using Truecrypt with Windows 8 should be considered unstable and a "hack" at best.
Assuming you can access your computer's BIOS menu, and you have a Windows ISO (XP, Vista, Seven, or 8), I would advise the following:
This should overwrite TrueCrypt's bootloader, and make it possible to resume the setup. It is also possible that something went wrong with the setup, in which case you will have to start over, using the Windows 8 ISO.