About "Reboot and select proper Boot Device" in Windows 8
For Windows users, “Reboot and Select Proper Boot Device” is a common error. Typically, when your computer system’s BIOS cannot find the bootable drive or recognize the drive where your operating system is installed, this error message will appear. Sometimes, it even freezes your computer, prevents your keyboard from working normally. In most cases, even if your reboot your computer, the message still pops up and Windows fails to start.
To help you easily troubleshoot such a problem, next we will show you what causes this error and effective fixes.
Why does my computer says "Reboot and select proper boot device"?
Any of the following factors could trigger this problem:
•The boot disk is not connected properly, or the disk has been damaged or failed.
•The boot disk is connected through a faulty cable, damaged SATA slot, so it cannot be detected by BIOS.
•Wrong boot sequence in BIOS.
•The partition which stores the Windows boot files is not set as active, then the Windows will be unbootable.
•Master Boot Record (MBR) is damaged or corrupted.
•Boot files get lost or corrupted.
•CMOS battery is failing.
How to fix "Reboot and select proper Boot Device” on Windows?
Since so many factors could result in such an error in Windows 10/8/7, it will be challenging for most users to find the exact cause and take the corresponding measure. Luckily, in the next part, we offer different solutions for every possible cause, so you can try them one by one until the error is removed in Windows.
1. Make sure the BIOS detects the boot disk successfully
First of all, you should check whether the boot disk is detected by BIOS. Reboot your computer and constantly press on F2, Del, or other required keys to enter BIOS before Windows is loaded. Then use the arrow key to access to “Main” tab where you can see all the drives detected by BIOS.
If the boot disk isn’t listed here, you need to shut down your computer, reconnect it via another cable or SATA slot. If the boot disk still does not show up here then, the boot drive probably has been dead or damaged. Please replace it with a new one to see whether the problem can be fixed.
However, if the boot disk is already here, that means the BIOS has detected it successfully, so the “Reboot and Select Proper Boot Device” error should result from some logical causes, then you need to go for the following technical methods.
2. Change boot order
If the disk that loads the operating system is not set as the first boot device, then you will encounter the boot failure issue. If so, please change the boot order and set the disk as the bootable device.
1) Press the Power button and keep pressing a required key to enter BIOS.
2) Press the arrow key on your keyboard to get the Boot tab, and change the boot order settings to list boot disk first.
3) Follow the instruction given to you in the BIOS utility to navigate to the Exit tab.
4) Locate and choose the Exit Saving Changes option to save the changes.
5) Restart your computer.
3. Reset primary partition as active
To remove "Reboot and Select Proper Boot Device" in Windows 10/8/7, you can also try to reset the primary partition as active.
First, insert the Windows installation media and boot your computer from that, then under System Recovery Options or Troubleshoot, click Command Prompt, finally type the following commands in sequence and hit enter after each: diskpart -> select disk 0 -> list partition 1 -> active. Select the boot partition number.
4. Rebuild damaged MBR
When the MBR gets damaged, the windows might show a black screen and ask you to insert boot media. Under this situation, you can try to rebuild MBR. To do this in Windows 10/8/7, you might need third-party software. AOMEI Partition Assistant Standard is exactly what you can rely on. It could help you rebuild damaged MBR without an original Windows installation disc.
Before you do: please connect an empty USB (over 8GB) to a working computer, download the freeware, install and run it to make a bootable USB by clicking Make Bootable Media in the left panel. (Note: The bootable USB will contain installed AOMEI Partition Assistant.)
Then do as below:
1) Insert the bootable USB into the computer with the “Reboot and Select Proper Boot Device” problem. Boot it from the USB by changing boot order in BIOS.
2) You’ll see loaded AOMEI Partition Assistant once log in. Right-click the system disk and select Rebuild MBR.
3) Choose a proper MBR type for the current OS you are using.
4) Back to the main interface, click Apply -> Proceed to start rebuilding the MBR.
Then, the MBR is rebuilt completely. Besides that, this versatile software could also help you check bad sectors on the hard drive.
5. Repair corrupted boot files from Command Prompt
Boot from your Windows installation disk. In the Windows setup screen. Select the language and region, and click Repair your computer, then Troubleshoot->Command Prompt to open the Command prompt window, finally type the commands below and hit Enter after each one.
After that, Exit Command Prompt and restart your computer.
6. Replace the failing CMOS battery
The CMOS battery is a small circular cell located in your motherboard. If it is damaged or failing, there are chances that you will meet the "Reboot and select proper Boot device" error. Then, you can open your computer's casing, access the motherboard, and uninstall the CMOS battery. Hold the power button for seconds to free up any residual charge. At last, replace the CMOS battery with a working one.
With so many different solutions, you are sure to easily tackle with “Reboot and Select Proper Boot Device” in Windows 10/8/7. Although some methods require the Windows installation disc, you can choose AOMEI Partition Assistant that makes the whole process as easy as possible. For more advanced features like recover lost partitions in Windows 10/8/7, allocate free space from one partition to another, convert disk between MBR and GPT without deleting partitions, you can upgrade to the Pro version.