The Windows 10 upgrade on my Lenovo X1 Carbon Touch (Gen 1) failed today and I didn't immediately find the solution online. I wanted to document the error and how I eventually completed the installation in hopes that it helps others.
I was upgrading from Windows 8.1. During the installation I got a Blue Screen of Death error message similar to the following, except the error was CRITICAL_PROCESS_DIED
The "collecting some error info" process never completed so I had to do a hard reset. At this point I started worrying that a full reinstall was going to be necessary. Based on my previous experience with major Windows OS upgrades, a BSOD error message is never a good thing.
Always Backup First!
As an aside, it's always a good idea to back up all your important files before doing a major OS upgrade. Just in case!
After the reboot, I was pleasantly surprised to see the installation had completely rolled back to my previous Windows version. No "Safe Mode" or "System Restore" needed. This graceful rollback really helps non-technical users so I appreciate the effort Microsoft put into the upgrade process.
Up popped the "Windows Update" window with a more specific error code of C1900101-4001E. A quick Google search of the error code only turned up a 22 page Microsoft Answers thread with no real solution.
This led my thinking back to the original CRITICAL_PROCESS_DIED BSOD. I decided to check the Lenovo support page to see if Windows 10 drivers were available. Indeed they were, as well as a BIOS update. I downloaded and updated every driver that mentioned Windows 10.
The weird thing is that one of the steps of the Windows 10 installation process is "Installing features and drivers". I assumed that would update all the drivers to the necessary versions, so maybe it was the BIOS update that fixed the problem.
Finally I restarted the Windows 10 upgrade. For some unknown reason, Windows Update had to download the entire 2.67 GB again so more waiting. But luckily the installation completed successfully!
So if you're having trouble upgrading to Windows 10, try updating your BIOS and drivers BEFORE you start the installation.