When the computer starts up, the BIOS tries to find an operating system on the hard drive that it can boot. However, if nothing is found, the error “Operating system not found” is displayed. This could be due to an error in the BIOS setup, a faulty hard drive, or a corrupted MBR.
Fix “Operating system not found” startup error for Windows XP, Vista, 7, 8, 8.1 or Windows 10.
This error is also common on Sony VIO laptops, including the Ultra T and S series books.
When your computer boots up, the BIOS will find a system on your hard drive to boot. If there is no system, the computer does not know where to go and you will receive a message to resolve the problem. Here are the main reasons for the lack of a Windows operating system.
How To Fix The “Operating System Not Found” Error
Restart your computer . The “Operating system not found” error can be a temporary error that can be fixed by restarting.
Disconnect unnecessary flash drives, remove the disc, if present, and remove the floppy disks. Your computer may be trying to find a suitable operating system on one of these devices. If this is not possible, you may see an “Operating system not found” error.
This is important because your computer assumes that there is no operating system to boot if something else, such as a flash drive or disk, takes precedence, but there is no operating system on it, and that no operating system is found “starting” – error.
Enable or disable UEFI Secure Boot, whichever is currently installed. Starting Windows in UEFI mode depends on whether it is in a GUID partition table or on a MBR floppy disk. Enabling or disabling Secure Boot can determine if the error is related.
To do this, use the BIOS setup utility (to access it, see the link in step 3) on the Security tab. Change the safe start to the current value, i.e. enabled or disabled.
After this step, restart your computer. If you still receive an operating system not found error, reset this setting to its original value and skip to the next step.proposal.
Reset BIOS to factory default . Undoing each BIOS setting can reset something that was previously hiding the hard drive or interfering with OS detection.
The easiest way to resolve an Operating System Not Found error during a BIOS reset is to look for the reset option in BIOS setup. This could be a function key like F9 that you need to press, or a menu item called BIOS Reset. The exact steps to be taken depend on the BIOS manufacturer.
Restore the startup records to resolve the “Operating System Not Found” error. Valid boot records are required for the normal boot process. If the Master Boot Record (MBR) or Boot Configuration Record (BCD) memory is damaged or missing, you might see an “Operating System Not Found” error.
Since you are unable to access Windows due to an error, you will need to use an installation CD or flash drive to access the recovery tools we are talking about in In the next and next steps. Find out how to do it on Windows 10 and 8 here; Windows 7 ( here ) and Vista ( here ) users can follow similar steps.
bootrec.exe / rebuildbcd
After running the previous command, while still on the command line, enter:
bootrec.exe / fixmbr
Finally, restart your computer to see if the “Operating system not found” error has been resolved.
Use the diskpart command to activate the partition on which Windows is installed. It could have been disabled for some reason, which explains why the “Operating system not found” error is displayed.
Enter the command prompt from the installation CD by following the same steps as above, then enter this command:
List of hard drives
Use this command to select the hard drive that matches the hard drive where theOperating system (most users will only see one in the list):
Select disk 0
Use this command to list all partitions on this hard drive:
Enter this to select the partition on your hard drive where Windows is installed:
Select volume 2
Turn up the volume with this command:
If you’ve fixed the “Operating system not found” error, Windows should start normally on reboot. Exit the command prompt and click Next to start the operating system.
Reinstall the hard drive power and data cables . Disconnected or loose cables can cause an “Operating system not found” error.
Reinstall the Windows operating system . The “Operating system not found” error can be literal. Malicious software or unwanted formatting may have removed the operating system from the hard drive.
If you cannot access the hard drive to reinstall the operating systemsystems, the last option is step 10.
At the moment, a faulty hard drive is the only reason you are still getting the error. Replace hard drive and install a new version of the operating system to resolve the “Operating system not found” error.
The “Operating system not found” error can appear on any computer running Windows 10, Windows 8, Windows 7, Windows Vista, or Windows XP.
Since you cannot access Windows due to an error, you will need to use an installation CD or flash drive to access the recovery tools we are talking about in this and the next steps. Find out how to do it on Windows 10 and 8 here; Windows 7 ( here ) and Vista ( here ) users can follow similar steps.
Thank you for letting us know!