How to fix “Reboot and Select proper Boot Device”

The “Reboot and select proper boot device” error seems relatively self-explanatory: Restart your computer and select the hardware that your system uses to boot up. But what’s the best way to resolve this issue?

The “reboot and select proper boot device” error message that appears on the black screen before Windows starts up, in most cases, is due to one of the following causes:

• Wrong hard drive selected in the BIOS
• Windows boot loader is not working properly or is not detecting the hard drive
• Hard drive has a hardware error.

The first step to solving the error is to narrow down its cause. In most cases, the error can be fixed.

Often a weak BIOS battery or an incorrect BIOS setting is the only reason that your hard drive is not being recognized and your PC won’t boot.

1. To make changes in the BIOS, you’ll need to press a certain key to access the BIOS setup during the booting process. For the vast majority of computers, press [Delete] or [F2] when the prompt appears on screen during startup.
2. In the BIOS Setup program, you’ll see the option to reset BIOS to default settings. This is sufficient in most cases.
3. If that doesn’t help, check the hard drives that are listed in the BIOS. Usually, a PC boots from the first hard drive. In the BIOS Setup program, you can set the order in which the hardware searches the drives for a boot sector. “Reboot and select proper boot device” or the “OS not found” error messages could also mean that there is no operating system installed on the drive from which your PC wants to boot.
4. The BIOS automatically detects the connected hard drive and enters the appropriate hardware parameters. This process usually works well in most cases. If there’s an issue, the hard drive will be displayed in the BIOS with a size that is obviously incorrect, and the drive won't be detected in Windows at all. Most BIOS versions provide a so-called custom type on the hard drive so that you can enter the hardware parameters yourself. If you can't find them directly on your hard drive, consult the manufacturer's specifications.
5. In some BIOS versions, it also helps to set the system hard drive as the default boot drive and to disable the optional graphical boot menu.
6. After making your changes, save the BIOS settings (usually by pressing the F10 key) and restart your PC.

If the BIOS is set correctly and the PC still displays the “reboot and select proper boot device” error at startup, the Windows system repair options can help you repair the boot loader.

1. Since this type of error means that the Windows 10 boot loader can no longer be found, boot your computer from a Windows installation DVD or a bootable USB drive containing the Windows installation files. The Start menu of these installation media contains advanced boot options that allow you to repair the operating system or recover your data.
2. First, choose your language and click “Repair your computer” on the next page of the installer, since you don’t want to completely reinstall Windows.
3. On the next screen, click “Choose an Option” and “Troubleshoot.” You can also use this option to troubleshoot error messages if Windows is not starting.
4. The troubleshooting option takes you to another dialog window where you can restore your PC to the factory settings. This is only necessary if all the other repair methods don’t help.
5. You can choose “Advanced Options” for additional system repair options that will often help you get a damaged Windows system back up and running.
6. If the boot sector on the hard drive is the reason that Windows will not start (a very common reason, by the way), the Startup Repair tool can be helpful.

Run Startup Repair until it finishes, which can take a few minutes, and then select Restart in the repair options. Remove the Windows DVD from the drive or disconnect the USB drive and then restart the PC.

Sometimes Startup Repair cannot fix this problem. In that case, you can write a whole new boot sector to the hard drive. This method has been available as of Windows 8.1 and Windows 7.

1. With this method, you boot your computer from a Windows installation DVD, just like you did above. Choose your language and click “Repair your computer” on the next page of the installer.
2. On the next screen, select “Choose an Option” -> “Troubleshoot” -> “Advanced Options” -> “Command Prompt.”
3. Now type the following command: bootrec /fixmbr
4. This command writes a new master boot record to the hard drive. Next, type bootrec /fixboot
5. This command writes a new boot sector to the disk in order to replace a boot loader that may have been overwritten by an older version of Windows.
6. Choose exit to close Command Prompt and select restart in the repair options. This time, restart from your hard drive, not from the Windows DVD.

If your hard drive has a hardware error, the problem might sound more catastrophic than it actually is. In many cases, the culprit might simply be defective connecting cables. Almost all modern PCs use a SATA interface to connect hard drives. These cables are not made to last forever. The tiny contacts of the connections get dusty or corrode over time, and even the slightest kink in the cable can cause your computer to no longer recognize the connected hard drive.

1. Disconnect your PC from the power source. Then disconnect the SATA cable from the hard drive and motherboard, and clean the contacts with a lint-free alcohol wipe. Reconnect the cable and reboot the PC. Often this will solve the problem. Alternatively, you can try using another SATA cable.
2. If you've ruled out the SATA cables as the cause of the error, remove the hard drive while the PC is turned off and try it in another PC. A hard drive that has a hardware defect in its boot sector is by no means unusable.
3. Once you've installed the hard drive as a second drive in the other PC, you first have to set the boot order in the BIOS so that the PC continues to boot from its functioning Windows system hard drive.
4. When Windows starts up, the second hard drive appears as a new drive in the File Explorer, as long as its file system is still recognized by the operating system.
5. Right-click the drive in the File Explorer, select “Properties,” go to the “Tools” tab and click “Check.”
6. You can then choose the checks that you want to run. Run a complete scan, including recovery of bad sectors.
7. After that, try to back up as much data as possible from the hard drive. A hard drive with a hardware defect should no longer be used for important data. It’s highly likely that other sectors will also have errors in the future.
8. If you were unable to resolve the issue using the repair feature in the File Explorer, right-click the Windows logo in the taskbar to run Command Prompt as an administrator and try to repair the hard drive with the chkdsk command. You stand a good chance of recovering data this way.

Replace the hard drive once you've successfully backed up your data.