Couldn't update to Windows 8.1 - 0xC1900101 - 0x40017
Method 1: Perform hardware clean boot.
Sometimes external devices interfere the update process. It's best to eliminate this probability by disconnecting all unnecessary external devices connected to the computer (except the mouse and keyboard.
Method 2: Update the devices drivers on the computer.
Go to the Windows update program by going to start > type "Windows update" on the search box > check for the important and optional updates > Install.
IF there's no updates for the driver listed, go to the manufacturers website, on the download section type the exact model number of the computer and manually check for driver updates.