So you are starting your Windows, suddenly you are pontificated with the message on a black screen “Missing Operating System” or “Operating System Not Found” and you are unable to boot into your system, just imagine how annoying it would be if you were in an emergency.

Dealing with this error firstly and deeply calls for you to be familiar with the causes of this very error. Only that way you will be able to rectify it in better terms. So the basic causes for Missing Operating System are somewhat like these:

  • Improper or wrong BIOS settings unknowingly made by the users.
  • The failure of hard disk.
  • The failure of BIOS to detect the hard disk that installs Windows.
  • MBR (Windows Master Boot Record) in the hard drive might have been corrupted.
  • Users might have set wrong partition or the partition which saves the Windows boot files is no longer functional.

After you have got an acquaintanceship of the possible causes for this error, it would easier for you to understand the solutions made out below to rectify this error.

Method #1: Check If Hard disk Is Detected by BIOS

Here we would check if the hard disk is actually being recognized by your Basic Input/ Output (BIOS) System or not. That would give you an idea of what next step should be prevalent to tackle the situation.

Step 1. Power on your system and keep holding the “F12/F10” function keys until the BIOS utility settings page turns up.

Step 2. Now on the blue screen, check the status of three options namely –

  • IDE Primary Master
  • IDE Secondary Master
  • IDE Primary Slave

Check if Hard disk is detected by BIOS

If they are displayed to be “Detected”, then there is no issue with the hard disk recognition at all, but if it shows “Not detected”, then it is serious matter of concern.

Step 3. No worries, on encountering “Not detected” status, all that you have to do is to choose “None to Auto” option to set it right.

Step 4. Next if the system disk information is shown on screen, it indicates that you need to exit the BIOS and the BIOS can now detect the hard drive after you power it on freshly again.

Also read: How to Fix “Windows Can’t Add PIN Code” Error?

Method #2: Test Your Hard Disk Drive

Here we would test the hard disk drives to check if the hard disk is fine or not. if the test results turns out to be negative, then you surely need to replace your Hard disk as that is the main primary cause of the Missing operating system error. The steps are lined up ahead:

Step 1. While turning on your PC first, press Power button and F10 both.

Step 2. Once the PC displays you the Test screen, release the F10 and power button.

Step 3. Click on “Tools” menu in the BIOS utility settings.

Step 4. Next select “Hard drive self test” and press “Enter” to begin the text procedure.

Hard drive self test

Step 5. If the hard drive passes all the tests, then your hard drive is absolutely fine, and you need to switch over to the next method and if the tests fail, you must immediately contact your hard disk and computer manufacturer for a replacement.


Method #3: Set BIOS to Default Settings

Many a times, users or someone else erringly mess up with the BIOS setting, which invokes this very error to surface. So if you can set the BIOS settings back to the default conditions, then the issue of “Missing operating system” will not likely to resurface again. 

Step 1. Firstly restart your PC and enter BIOS by pressing F10/F12 function keys while powering it on.

Step 2. Now here you have to enable the “default setup option” in addition to Get Default Values; Load Optimal Defaults; Load Optimized Defaults; Load Setup Defaults, and etc.

set BIOS to default

Step 3. After you have set all the default setting options, press the F10 key to save the changes you just made.

And that’s all for this method. There still more solutions here for you reference to fix “operating system not found” issue. 


These 3 solutions above may help you fix and locate the issue of “operating system is missing”. If the problem is still prevalent, then it must be due to the corrupted MBR (Master Boot Record) disk. Now this is something, that you should not tackle yourself if you are not familiar with the technical atrocities of computer. In that case you better call it for the day and opt for a technician assistance that is adept with the hardware intricacies.


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