Windows 10 Won't Boot: Reboot Selection Problem Changing System Partition
Windows 10 is a popular and widely used operating system, but sometimes users may encounter issues when changing the system partition. One such problem is when the system fails to boot, and a message appears on the BIOS screen prompting the user to "Reboot and select proper Boot device." This article will cover the possible causes of this issue and provide solutions to help you get your Windows 10 system up and running again.
Understanding System Partitions
A system partition is a dedicated space on a hard drive or solid-state drive (SSD) that contains the operating system's files and necessary boot loaders. In the case of Windows 10, the system partition typically contains the boot manager, BCD (Boot Configuration Data), and other essential files required for the system to boot.
Causes of the Reboot Selection Problem
The "Reboot and select proper Boot device" message usually appears when the system cannot find the necessary boot files on the designated system partition. This issue can occur due to several reasons, including:
- Resizing or moving the system partition
- Changing the active partition
- Corrupted boot files
- Incorrect BIOS or UEFI settings
Fixing the Reboot Selection Problem
To resolve the boot selection problem, follow these steps:
Step 1: Access the BIOS or UEFI settings
Restart your computer and press the appropriate key (usually F2, F10, F12, or DEL) to enter the BIOS or UEFI settings. Consult your computer or motherboard manual for the specific key.
Step 2: Check the boot order
Ensure that the correct boot device (usually the hard drive or SSD containing the system partition) is set as the first boot device. Save and exit the BIOS or UEFI settings.
Step 3: Use Windows Recovery Environment (WinRE)
If the system still fails to boot, you can use the Windows Recovery Environment. To access WinRE, restart your computer and repeatedly press the F8 key during startup. Select "Troubleshoot" > "Advanced options" > "Command Prompt."
Step 4: Repair the boot files
In the Command Prompt, run the following commands:
bootrec /fixmbr
bootrec /fixboot
bootrec /rebuildbcd
These commands will repair the master boot record (MBR), rebuild the boot sector, and scan for Windows installations to add to the BCD store.
Step 5: Set the system partition as active
Use the diskpart utility to set the system partition as active:
diskpart
list disk
select disk [disk number]
list partition
select partition [system partition number]
active
exit
References
- Microsoft. (2021). Use Bootrec.exe in Windows RE to troubleshoot startup issues
- Microsoft. (2021). What is the system partition?
By following the steps outlined in this article, you should be able to resolve the "Reboot and select proper Boot device" issue and successfully boot your Windows 10 system.