What to do if the operating system is not found. Operating system not found - An operating system wasn't found. Reset BIOS to factory settings

One of the most terrible user errors is the one that appears when turning on the computer and tells us, on a black BIOS screen, that "". When this message appears, our system will not be able to boot, and the only way out is to restart the computer by pressing “ctrl+ alt+del”, and you will most likely see this message again An operating system wasn't found. Try disconnecting any drives that don't contain an operating system. Press Ctrl+ Alt+Del to restart.

The problem with the error is that the operating system is not displayed and therefore the BIOS cannot boot the Windows system. The reasons for this error are very varied: from a simple configuration error in the BIOS to a more serious problem that, in the worst case, forces us to completely format the computer. Therefore, we will analyze the main reasons and their solutions to eliminate the error "" ( An operating system wasn't found).

Disconnecting external USB devices from the computer

If your computer has multiple internal hard drives, external drives, and USB flash drives connected, it is likely that The BIOS is trying to find the operating system in the wrong place. Consequently, not detecting the Windows system, it displays the error “No operating system found.”

To resolve this issue, you need to unplug all external storage devices connected to the USB ports and try again. We can also check our optical drive to make sure it is not trying to load the wrong DVD.

If after doing this the problem is still not resolved, the next step is to go to BIOS settings.

Changing BIOS boot priority

Enter the BIOS configuration by pressing the F2, F12 or Delete buttons. After that, go to the configuration section Boot and put it first in the column Priority a hard drive on which the working and main Windows operating system is located. It is called differently in different BIOS versions, but you are looking for the word with the combination Priority, which means “priority boot”. Here are a few names from different BIOS: Hard Disk Priority, Boot Device Priority, Hard Disk Boot Priority.

May be useful:. There you will find approximately where to look Priority,

After you have set the boot priority from the hard drive on which your system is located, do not forget to save the settings using the F10 button and restart the computer to make sure that the system is “found when you turn on the computer.”

Enable or disable Secure Boot

If you are using a modern computer with an operating system such as Windows 8 or Windows 10, then perhaps the reason why our Windows will not start is in incorrect UEFI Secure Boot configuration.

Go back to BIOS, find the configuration section Secure Boot(Secure Boot) and deactivate it or activate it if it is disabled to check if the "Operating system not found when starting the computer" error disappears.

In different versions of BIOS or UEFI, the location of the settings looks different, but in any version of the BIOS you look for the column Secure Boot, try disabling or enabling.

Reset BIOS to factory settings

At the bottom of the BIOS menu you will see a key for default settings or reset BIOS. On my car this is F9. Confirm your decision when prompted and restart your computer.

If you haven’t found an example button like F9 to reset settings to factory settings, then look for the line Load Setup Default and reset the BIOS.

If your hard drive with the operating system is placed first, but the computer still does not boot, it is possible that some of the initial sectors of the drive have been damaged, such as master boot record(MBR), DOS boot entry(DBR) , or Boot Configuration Database(BCD).

Repairing these sectors is quite simple. All we need is to start the computer from a USB or Windows DVD. You can, for example, or just start with and select “System Restore” when installing Windows.

Type the following commands into CMD in order by pressing enter. Each command may take time to complete.

bootrec.exe /fixmbr
bootrec.exe /fixboot
bootrec.exe /rebuildbcd

Activate the Windows partition

It is possible that the partition on which Windows is installed is disabled. You can fix this using Windows' native diskpart tool. To complete the next steps, you will again need a USB drive to install Windows. Run the command line as described above, via a recovery disk or Windows installation flash drive and enter the following commands in the command line:

diskpart- Launch the tool.
list disk- List of connected drives to the computer.
select disk 0- Select the hard drive on which you want to activate the partition. In my case, the main hard drive is 0.
list volume- Shows partitions on the selected hard drive.
select volume 2- Select a local disk for activation. Choose the one where the widows system itself is installed.
active- Activate the section.

Restart your computer and make sure the error when turning on the computer disappears An operating system wasn't found. Try disconnecting any drives that don't contain an operating system. Press Ctrl+ Alt+Del to restart, which means operating system not found, click to reboot ctrl+alt+del.

There is probably no need to explain how unpleasant the situation is when the user turns on the computer or laptop to boot and instead of the usual start, the system, for no reason at all, writes Operating System not found on the screen. This comes as a real shock to many users. How so? Yesterday everything worked... We’ll now see what could have happened and how to correct this situation.

What does the Operating System not found error mean?

If you look at the message itself, it is not difficult to translate it as “operating system not found.” But the problem is that the user is absolutely sure that it exists. But the computer system does not share such confidence with the user, since it simply does not find the components responsible for loading the system.

In general, such situations most often occur, for example, when the user removed the hard drive and replaced it with a new one. Maybe the hard drive just failed, but you never know.

Possible causes

If suddenly such an incident occurs, and the system constantly displays the message Operating System not found (Windows 7, 8, etc.), first of all, do not panic. To get started, just check to see if a flash drive is inserted into your computer or laptop, and in the BIOS settings the USB device is the priority for booting.

If the hard drive was removed or replaced with a new one (this applies to desktop computers), it is very possible that when it was reconnected, the corresponding cables were connected incorrectly or loosely. Let's see what can be done in such a situation.

Basic BIOS settings

The easiest way to change BIOS settings is to reset all settings to factory defaults (Default). Any BIOS version has this setting.

As a last resort, you can simply change the boot priority in the Boot Device Priority or Boot Sequence section, and install the hard drive as the first (main) boot device.

It also happens, however, that the hard drive is detected in the BIOS, but booting still does not occur, and the system issues the Operating System not found warning again and again. What to do in such a situation? First, see if there is a hard drive model next to it. It signals that the device in the system, although present, is simply disabled or not used.

As a rule, in most BIOS versions there is a special device help field on the right (Specific Item Help), which contains a key combination that allows you to enable or disable any component. The most likely combination is Shift + 1. But here everything depends on the manufacturer (combinations may be different).

Switching hard drive operating modes in BIOS UEFI

On the other hand, if the Operating System not found warning appears on a laptop where removing the hard drive is quite problematic, you should pay special attention to the settings of the hard drive operating modes. As an example, let's look at the settings of the latest UEFI system, although they can be used without problems in other versions.

In general, there are two main modes in a SATA configuration: AHCI and IDE. During the initial installation of the OS, as well as in the default settings, AHCI mode is enabled. When you switch to the IDE, no matter how hard you try, you will not be able to install Windows on the hard drive.

The same applies to moments when users, at the end of the installation process, either unknowingly or accidentally turn on the IDE mode. As is already clear, the system displays the line Operating System not found. By the way, even if you install another fully functional “screw” at the moment, it will also not work without changing the SATA settings to the initial ones.

Therefore, we should immediately advise users to change such settings only as a last resort, when it is really necessary.

Recovering the Windows bootloader

There are also frequent cases when the message “Operating System not found” appears when the Windows bootloader is damaged, which is associated only with errors on the hard drive, for example, due to incorrect shutdown. In this case, as is already clear, the entire system can “fly off”.

In such a situation, you can try to restore the bootloader, and at the same time check the system disk or partition for errors. To do this, it is always advisable to have the original installation disk or system recovery disk at hand.

Here you will need to set the optical drive in the BIOS as the first priority boot device, and then use Note that in this option there is no question of restoring Windows from a checkpoint. This still won't help, and the Operating System not found warning will appear again.

Here you need to use boot recovery mode or the command line, which is preferable. In it, you need to enter two main commands in sequence: bootrec.exe /FixMbr and bootrec.exe /FixBoot, after each pressing “Enter”. If this sequence does not help, you can also add the bootrec.exe /RebuildBcd command.

Before performing such actions, it is strongly recommended to check for errors and automatically correct them (chkdsk /f /r or chkdsk /f /x /r commands). You can also use the chkntfs /x c: check tool, provided that there is an NTFS file system on the system partition (drive “C”).

If all else fails

However, if all the above methods for correcting the situation do not help, then you should definitely diagnose the hard drive. But if removing it is not a problem, then you will have to go to the nearest service center or workshop with the laptop and do not try to remove it yourself.

As is already clear, if the hard drive falls apart, there’s nothing you can do, you’ll have to replace it with new hardware, and then install the operating system again. You can, of course, try the utility on it, but it is quite difficult to guarantee one hundred percent success.