Why Does My Computer Say Non-system Disk or Disk Error

So, when I booted up my computer today, it came up with an error saying, 'Non-system disk or disk error.' What should I do to fix the startup issue and access my Windows desktop? Can someone help me with this? Thanks in advance!

There are many possible factors why you receive the message saying non-system disk or disk error and are unable to boot up the PC:

  • Faulty cable for HDD and motherboard
  • Misconfiguration of boot media
  • Bad sectors
  • Corrupted master boot record
  • Inactive system partition

Now you know the possible reasons behind the issue, let's learn how to fix it. First, you may want to clone the damaged drive to another to back up data on it. EaseUS Partition Master Professional can help you to manage that.

After the backup, check the solutions below to repair your disk:

Solution 1. Check Peripherals

Go and check if your HDD's IDE or SATA cables are connected properly and if removing certain storage devices can resolve the problem. 

Solution 2. Check Boot Priority in BIOS/UEFI

Step 1. Press BIOS hotkeys (Usually Esc, F2, F8, F10) while rebooting to enter the BIOS or UEFI setup screen.

Step 2. In BIOS, go to the Boot tab and set your system drive as the boot priority. In UEFI, you can use the mouse pointer to change the boot drive. (The UEFI interfaces vary in different computer manufacturers and firmware versions.)

Step 3. Save and exit.

Solution 3. Rebuild MBR

The reliable and powerful tool mentioned above also has the ability to repair MBR and is able to fix many other common errors in your system.

Step 1. Create a WinPE bootable disk with EaseUS Partition Master's "Bootable Media" feature

Step 2. Connect the bootable USB to your PC, enter the BIOS, and set the PC to boot from your USB drive.

Step 3. Launch EaseUS Partition Master and click "Toolkit" > "Rebuild MBR."

Step 4. Select the target disk and MBR type, then click "Rebuild" to start.