Hi Gallet,

Basically, the “Reboot and Select Proper Boot Device” error shows up when your computer system’s BIOS is having some trouble finding the bootable drive or other bootable devices. To put it another way, the BIOS chip in your computer’s motherboard is not able to recognize the drive where your operating system is installed.

You can follow the instructions below to resolve the issue:

1. Turn off your computer.
2. Boot it by pressing the Power button.
3. Press the appropriate button to enter the BIOS settings. The key varies depending on the brand of the computer you have. It is best to consult your user manual, but generally, it can be the F12, F2, ESC, or Delete key.
4. Once you get inside the BIOS Setup Utility, go to Boot Options. Set the operating system drive as the primary boot device. Use the arrow key to move it to the top of the list.
5. Save the changes you made and restart your computer.

Method 1: Checking and fixing problems on your system’s drive

The problem may come from your computer’s OS drive. So, the first thing you have to do is check whether your SDD or HDD is properly connected to your computer. You can easily do this by entering the BIOS settings. With that said, follow the steps below:

1. Shut down your computer.
2. Press the Power button to turn it on.
3. Enter the BIOS settings by pressing the appropriate key. Read your computer’s manufacturer manual to know the corresponding key for the BIOS settings. In general, it can be the F12, F2, ESC, or Delete key.
4. After entering the BIOS Setup Utility window, go to Main Settings or Standard CMOS Features.
5. Check if your system’s SDD or HDD is listed on this page.

If you learn that your system’s drive is not mentioned in the BIOS menu, then it is likely that your HDD or SDD is not properly connected to your computer. The cables may be faulty or your main storage device may have ceased to function. In this case, you would have to open your computer’s casing and replace the SATA cable with a new one. Just to make sure that all the cables are properly functioning, you can also replace your storage device’s power connector. If you’re not confident to do this on your own, it is best to seek a professional to help you.

Method 2: Using diskpart

The “Reboot and select proper boot device” error can also happen if the computer’s active drive is not configured to be the primary hard drive. You can fix this problem by setting your primary hard drive as the active one. Here are the steps:

1. Insert your Windows installation disc or Recovery media into your computer.
2. Restart your computer and boot it from the media you just inserted.
3. Once you’re inside the System Recovery Options window, select Troubleshoot.
4. Under the Troubleshoot options, click Advanced Options.
5. Choose Command Prompt from the Advanced Options menu.
6. Inside the Command Prompt, type “diskpart” (no quotes), then hit Enter.

Note: X stands for the corresponding number of the disk where your operating system is installed. You can check the full list of disks on your computer by typing “list disk” (no quotes) in the Command Prompt.

1. Type the following commands one by one. Make sure you hit Enter after every command.

list partition
select partition X *Change X to the number of your primary partition*
active

Method 3: Replacing your CMOS battery

You will find the small, circular CMOS battery in your motherboard. If this cell is damaged or failing, it will cause various problems including the “Reboot and Select Proper Boot Device” error. In this case, you have to open your computer’s casing, access the motherboard, and remove the CMOS battery. Make sure you get rid of any residual charge by holding the Power button for at least 10 seconds. After that, replace the CMOS battery with a new one. Employing this method should fix the error.

I hope this helps.

Regards,
Lokesh