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

Same issue.

Custom Built:

ASUS Sabertooth Z87, Intel i7-Quad Core 4770K, 2x ASUS Geforce GTX 770 (SLI)

Is there a solution to this yet?

Thanks. I followed the steps for a clean boot, but, unfortunately the install failed at about 86%. The error message after Windows 8 was restored was: Error 0xC1900101 - 0x30018.

I managed to solve my problem, and successfully installed Windows 8.1 PRO.

Seems Windows 8.1 PRO didn't like that I had 1 pair of 2gb RAM memory sticks and 1 pair of 1gbs memory sticks. I removed all RAM sticks but one of the 2gb memory sticks and voila everything went smooth.

I don't like that advice to disable apps in task-manager.

First, it only disables stuff for the currents session, after a reboot, the incompatible programs will start up again.

Second, it doesn't tell you which applications to stop.

Third, it does not mention drivers that might not be compatible.

Do a clean boot instead. Setting up a clean boot using MSconfig will disable everything not needed by the update even after several boots-up, even the ones the update does when updating to 8.1

After, you complete the update and 8.1 is working, you can go into msconfig again and re-enable the non MS programs to start up normally.

Here is the basic steps for doing a clean boot. At the end of this post I included a link for all the details on setting up a clean boot and restoring the regular boot later, plus troubleshooting tips should you have a a problem with one application or driver.

Follow the following steps to perform a clean boot on Windows 8

Swipe in from the right edge of the screen, and then tap Search. Or, if you are using a mouse, point to the lower-right corner of the screen, and then click Search on the charms bar.

Type msconfig in the search box, and then tap or click msconfig.

On the Services tab of the System Configuration dialog box, tap or click to select the Hide all Microsoft services check box, and then tap or click Disable all.

On the Startup tab of the System Configuration dialog box, tap or click Open Task Manager.

On the Startup tab in Task Manager, for each startup item, select the item and then click Disable.

Close Task Manager.

On the Startup tab of the System Configuration dialog box, tap or click OK, and then restart the computer.

On the General tab, click the Selective startup option, and then click to clear the Load startup items check box. (The Use Original Boot.ini check box is unavailable.)

On the Services tab, click to select the Hide all Microsoft services check box, and then click Disable all.

*** When you hide all MS services, the remaining services are third party programs and extended driver features that are likely to mess up the update. you will see things like ExpressCache,Google Update, Nvidia, Logitech, etc. DISABLE ALL OF THEM *** (but don't disable any MS services)

Note This step lets Microsoft services continue to run. These services include Networking, Plug and Play, Event Logging, Error Reporting, and other services. If you disable these services, you may permanently delete all restore points. Do not do this if you want to use the System Restore utility together with existing restore points.

Click OK, and then click Restart.

Now go to the Store and run the 8.1 update.

By my estimation, this should work for about 80% of the people who posted to this topic.

If you have moved the \users folder to another drive by any method not approved by Microsoft, done any registry hacks or used any third party utilities that mess with the physical hard drives, the upgrade may still fail. You may have to remove all partitions from the physical boot disk and remove any Dynamic features from the drive. You should also unplug all USB devices except the keyboard and mouse, then turn off any Bluetooth devices.

A complete description for setting up a clean boot, along with restoring it to a normal boot and troubleshooting the apps that may not work on 8.1, along with screen shots can be found on the Microsoft site here: http://support.microsoft.com/kb/929135/en-us