Windows 10 Missing Operating System

 
As you know, nowadays Windows 10 operating system is becoming more and more popular all over the world, so many of you choose to upgrade to Windows 10 from Windows 7 or Windows 8.1. However, it is worthy of being mentioned that more and more problems appear after a upgrade, which makes you very upset. Among those problems, “operating system missing” issue is very common and you can find many forums about such a problem.
 
“I am using Windows 7, today I get update to Windows 10. After the update I have the problem “Missing operating system”. Anyone who know what is going wrong. I am using a ASUS X77J series laptop with SSD drive. Looking forward to some advice, above happened for the second time.”
 
When meeting such an issue, after you start your computer, it is possible that you will receive the following prompts without any cue to the solution. This indicates there is a failure to boot your computer.
 


 

Why Missing Operating System Windows 10 Upgrade

 
Once Windows 10 upgrade failed missing operating system issue appears, you may ask why. Generally speaking, the system can’t find the hard drive where Windows is installed in the process of booting the computer, and then the error occurs. Actually, there are four factors that lead to system not found issue.
 
• BIOS is unable to detect your hard drive with operating system.
• Master Boot Record (MBR) of your disk is corrupted.
• You haven’t set the partition which contains MBR active.
• Your hard drive is damaged.
 
After knowing the reasons to this error, it is time to take measures to repair it.
 

How to Fix Missing Operating System in Windows 10

 
When you fail to boot your system, it may be difficult to fix the issue. Perhaps reinstalling Windows operating system is a choice, however, if you don’t have a installation disc, it is not easy. Actually, this issue can be solved easily and quickly, just as the following sentences show to fix Windows 10 missing operating system issue.
 

Modify BIOS Boot Order

 
If your computer is unable to boot and can’t find operating system, the first thing you should consider whether the boot order is right or not in BIOS. In other words, you should boot from the hard disk where you have installed Windows 10 operating system.
 
1. Press the right key to enter into BIOS. In different computers, the way to go to BIOS is different.
2. Then under “Boot” tab, please set to boot from your target disk firstly.
3. Then save the change and restart your computer.
 

 

Set Partition Active

 
Here is another important thing, that is you must set the partition with boot files active, otherwise, it is possible to meet missing operating system Windows 10 upgrade issue. In this case, you can use a professional partition software – MiniTool Partition Wizard Bootable CD to do this work. In order to set right partition active, please download this software and then build a free bootable partition manager with Pwfree91.iso.
 
1. Please set to boot from the bootable media.
2. Then you will enter into its main interface after a few seconds.
3. Next you should check whether the boot partition is active. If it is not active, you need to use this partition manager to change it to be active with “Set Active” feature. At last, click “Apply” to perform the operation.
 

 

Fix MBR

 
The above mentioned corrupted MBR will cause “missing operating system” issue, so it is necessary to recreate MBR and fix it. Also you can use MiniTool Partition Wizard Bootable CD to do such a work. Just right click your target disk and select “Rebuild MBR” or click this feature in the left pane after selecting a disk.
 

 

Roll Back to the Previous Operating System

 
In addition, when the upgrading problem happens, some of you choose to roll back Windows 10 to Windows 7/8.1. This article is useful for you, please click here.
 
This post introduces you some ways to fix Windows 10 missing operating system issue, in fact, there are still other ways, so if you want to know much detailed information, 5 Solutions to Missing Operating System after Upgrading to Windows 10 is worth recommending.