Windows 10 has undoubtedly been the largest online update release till date with more than 67 million PCs already running Microsoft's latest desktop operating system (OS). The number of inherent bugs in the new OS has also grown substantially ever since the software released.
Windows 10 users are encountering the most common installation error 0xC1900101 - 0x20004, wherein the device gets stuck at 25% installation or when 84% of the files have been copied.
Apparently, the blue LED on the PC stops blinking and the system freezes when this error occurs, during the Windows 10 installation.
Folks at Bidness ETC have confirmed that performing a hard reset will inadvertently roll back your computer software to Windows 8.1 or 7, while Microsoft is yet to address this critical issue.
It has been identified that the root cause of this issue is linked to the difference in the way Windows 10 and Windows 7/8.1 interact with internal components and external peripherals.
Furthermore, Windows 10 users with more than one storage or optical disk drive such as SSD or HDD are said to be affected with this issue. However, there is a simple fix to resolve this problem:
Steps to fix Windows 10 stuck at 25% installation or error 0xC1900101 - 0x20004
Step 1: Ensure that you install Windows 10 via thumb drive or from a CD/DVD, as the Windows 10 update method is still buggy and unstable.
Step 2: Disconnect all peripherals or external devices connected to the PC, apart from the installation media or optical drive, keyboard, mouse and monitor.
Step 3: Also disconnect the SATA cable of your second DVD drive and extra storage drives, except the one on which you want to install Windows 10.
[Source: Bidness ETC]