1. Symptoms of the problem
When computer is powered up, the following error message appears:
An operating system wasn "t found. Try disconnecting any drives that don" t contain an operating system. Press Ctrl + Alt + Del to restart (white-on-black letters in text mode and blinking cursor):
2.Normal boot sequence
The rest of this article refers to Windows 10, but all information below applies to Windows 8 / 8.1 as well. (Windows 7 and Windows Vista never emit this error, instead they emit "BOOTMGR is missing".)
Normally Windows 10 boots as shown below:
- Master Boot Record scans partition table for active partition, then it loads 1st sector from active partition, verifies 55 AA signature, and transfers control to Boot Sector.
- Boot Sector loads 15 additional sectors from the beginning of disk (Volume Boot Record) and transfers control to first additional sector of VBR.
- Volume Boot Record loads BOOTMGR file from root directory of boot partition into the memory and transfers control to it.
- BOOTMGR loads Boot \ BCD registry hive and displays boot menu. BOOTMGR is able to run memory test and set safe mode boot flag per explicit user request. But normally, it loads winload.exe when computer boots normally (cold startup) or winresume.exe (when computer resumes from hibernation).
- Winload.exe opens SYSTEM registry hive, gets list of drivers, loads NTOSKRNL.exe, loads drivers (* .SYS files) and transfers control to NTOSKRNL.exe.
- Winresume.exe loads memory dump from hiberfil.sys and transfers control to it.
3. Defect in the boot sequence which leads to BOOTMGR is missing error
Defect in the boot sequence which leads to "An operating system wasn" t found "error is shown below:
- BIOS loads 1st sector from HDD (Master Boot Record), verifies 55 AA signature and transfers control to Master Boot Record.
- Master Boot Record scans partition table for active partition. There is one active partition, so Master Boot Record loads 1st sector from active partition (Boot Sector), and transfers control to it.
- Boot Sector loads the rest of Volume Boot Record and VBR tries to find BOOTMGR at the root directory of boot partition but fails because "BOOTMGR" file does not exist or not readable.
- The rest of usual boot events do not happen.
4. How to fix "An operating system wasn" t found "error
1) Download Emergency Boot Kit and deploy it to USB thumbdrive according to the instructions, then set up your BIOS to boot from USB thumbdrive. You need full version of Emergency Boot Kit to actually write changes to the disk, but it "s recommended to try demo version to make sure there are no hardware incompatibilities.
2) Boot into Emergency Boot Kit:
3) Run File Manager from the main menu:
4) Press Alt + F1 and choose your boot partition from the menu. For Windows 10 and Windows 8 / 8.1 this partition should have "System Reserved" volume label and is expected to be small (100-500MB). Use UP and DOWN arrow keys and ENTER to navigate the menu:
5) In this example, BOOTMGR file is missing from boot partition. If it exists in your environment, delete it (set cursor to the file using arrow keys UP and DOWN and then press F8). If BOOTMGR file is not deleteable, then rename it (for example, to BOOTMGR.OLD by pressing F6 key):
6) Insert Windows 10 installation USB thumbdrive to any of your computer "s USB ports and press Alt + F2. Choose Windows 10 installation USB thumbdrive drive from the menu using UP and DOWN arrow keys:
(Alternative approach: if don "t have Windows 10 installation USB thumbdrive, then you can recover a copy of this file from \ Windows \ Boot \ PCAT folder on your system partition)
8) Press TAB key to switch input focus to the right panel and navigate to the BOOTMGR file:
9) Press F5 to copy BOOTMGR to the left panel. Confirm with ENTER key:
One of the most frightening user errors is the one that appears when the computer is turned on 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. Ttry 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 and USB flash drives, it is likely that The BIOS is trying to find the operating system in the wrong place. Therefore, not detecting the Windows system, it gives the error "Operating system not found".
- To fix this problem, you need to disable all external devices connected to 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
Go to BIOS configuration by pressing F2, F12 or Delete. After that go to the configuration section Boot and put on the first place in the column PriorityHDD where the working and main operating Windows system... V different versions BIOS it is called differently, but you are looking for a word with a combination of Priority, which means "priority loading". Here are some names from different BIOSes: Hard disk Priority, Boot Device Priority, Hard Disk Boot Priority.
It may be useful:... There you will find roughly where to look Priority, but don't forget that there is a manual for the stick.
After you have set the priority for booting from the hard disk on which your system is located, do not forget to save the settings with the F10 button and restart the computer to make sure "whether the system was found when you turn on the computer."
Enable or disable Safe Boot
If you are using modern computer with operating system such as Windows 8 or Windows 10, then perhaps the reason our Windows won't start is in the wrong UEFI secure boot setting.
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 error "Operating system not found at computer startup" is gone.
In different BIOS or UEFI versions, the location of the settings looks different, but in any BIOS version you are looking for the column Secure boot, try to disable or enable.
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 F9. Confirm your decision when prompted and restart your computer.
If you did not find an approximate button, like F9 for resetting the settings to factory defaults, 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 won't boot, it is possible that some of the initial sectors of the drive were damaged, such as the main boot record (MBR), DOS boot record(DBR), or Boot configuration database(BCD).
Repairing these sectors is fairly straightforward. All we need to do is start the computer from a USB or Windows DVD. You can, for example, or just start with and select "system restore" when installing windows.
Enter the following commands in 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 own instrument diskpart Windows. To complete the following steps, you will need a USB media to install Windows again. Run Command Prompt as described above via recovery disc or installation USB flash drive and in command line type in the following commands:
- diskpart- Launching the tool.
- list disk- List of connected drives to the computer.
- select disk 0- Selecting the hard drive on which you want to activate the partition. In my case, the primary hard drive is 0.
- list volume- Shows partitions on the selected hard drive.
- select volume 2- Select local disk to activate. Choose the one where the widows system itself is installed.
- active- Activate the section.
Restart your computer and check if the error is gone when turning on the computer An operating system wasn "t found. Ttry disconnecting any drives that don" t contain an operating system. Press Ctrl + Alt + Del to restart, which means operating system not found, click to restart ctrl + alt + del.
Probably, there is 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 writes Operating System on the screen for no reason. not found... For many users, this is a real shock. How so? Yesterday everything worked ... What could have happened, and how to fix this situation, we will now see.
What does the Operating System not found error mean?
If you look at the message itself, it is easy to translate it as "operating system not found." But the problem is that the user is absolutely sure that it exists. And here computer system he does not share such confidence with the user, because he simply does not find the components responsible for loading the system.
In general, such situations are most often manifested, for example, when the user removed the hard drive, replaced it with a new one. Maybe the hard drive just failed, but you never know what.
Possible causes of occurrence
If you suddenly get such an incident, 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, maybe a flash drive is inserted into the computer or laptop, and BIOS settings the priority for downloading is the USB device.
If the hard drive was removed or changed to a new one (this applies to stationary computers), it may very well be that when it was reconnected, the corresponding loops were incorrectly or loosely connected. Let's see what can be done in such a situation.
Basic BIOS settings
The most in a simple way Changes to BIOS settings may reset all settings to the factory default settings (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 set the hard drive as the first (main) boot device (boot device).
It happens, however, that the hard drive is detected in the BIOS, but the boot is still not performed, and the system again and again issues the Operating System not found warning. What to do in such a situation? First, see if there is a hard disk in front of the model.It signals that the device in the system, although it is present, is simply disabled or not used.
As a rule, in most BIOS versions, there is a special item help field on the right (Specific Item Help), which contains a keyboard shortcut that allows you to enable or disable any component. The most likely combination is Shift + 1. But here it all depends on the manufacturer (combinations may be different).
Switching the operating modes of the hard drive in the BIOS UEFI
On the other hand, if the Operating System not found warning appears on a laptop, where it is quite problematic to remove the hard drive, you should pay special attention to the settings for the operating modes of the hard drive. As an example, consider the settings the latest system UEFI, although they can be used in other versions without problems.
In general, there are two main modes in the SATA configuration: AHCI and IDE. During the initial installation of the "operating system", as well as in the default settings, enabled AHCI mode... 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 the moments when users, at the end of the installation process, either unknowingly, or accidentally turn on the IDE mode. As already clear, the system produces the line Operating System not found. By the way, even if you install another fully functional "screw" at the moment, it will not work without changing the SATA settings to the initial ones.
Therefore, it is worth immediately advising users to change such settings only as a last resort, when it is really necessary.
Repairing 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 disk, for example, due to improper shutdown. At the same time, as it is already clear, the whole system can "fly off".
In such a situation, you can try to restore the bootloader, and at the same time check system disk or a section for errors. To do this, it is always advisable to have the original installation disc or a system recovery disk.
Here you will need to set the optical drive in the BIOS as the first priority device for booting, and then use Note, in this option there is no question about Windows recovery from the control point. It still won't help, and the Operating System not found warning will appear again.
Here you need to use boot recovery mode or command line, which is preferable. In it, you need to sequentially enter two main commands: bootrec.exe / FixMbr and bootrec.exe / FixBoot, after each pressing "Enter". If such a sequence does not help, in addition, you can add the bootrec.exe / RebuildBcd command.
Before performing such actions, it is strongly recommended to check for errors with their automatic correction (commands chkdsk / f / r or chkdsk / f / x / r). You can also use the chkntfs / x c: checker if you have a file NTFS systems in the system partition (drive "C").
If all else fails
However, if all the above methods of correcting the situation do not help, then you should definitely diagnose the hard drive. But if it's not a problem to remove it, then you will have to contact the nearest laptop with a laptop. service center or a workshop and do not try to remove it yourself.
As it is already clear, if the hard drive "fell down", there is nothing you can do about it, you will have to change it to a new "hardware", and then install the "operating system" again. You can, of course, try the action of the utility on it, but it is quite difficult to guarantee one hundred percent success.
During loading of the operating system (usually Windows 7,8,10), the user may encounter system message“An operating system wasn’t found. Try disconnecting any drives that don’t contain an operating system. Press Ctrl + Alt + Del to restart ". When you press the above keys, the computer restarts, after which this error may occur again. In this article I will tell you what is the essence of this problem, what are its causes and how to fix the error. « An operating system wasn’t found "on your PCs.
Screenshot of the error An operating system wasn’t found.
Translated from of English language the text of this message sounds like:
The operating system was not found. Try disconnecting any drives that do not contain an operating system. Press Ctrl + Alt + Del to restart ".
Usually this means a situation in which the OS did not find the operating system loader on the "rubble" disk (in particular, due to a damaged system partition), therefore it signaled this with the help of the above message.
In addition to the damaged system partition, the causes of the problem “An operating system wasn’t found. Try disconnecting any drives that don’t ... ”there may be insufficient tight connection of the loops hard disk with the corresponding connectors on the hard drive and motherboard, physical damage to the cables themselves, as well as external devices connected to the PC (external hard drive, flash drive, 3G modems, connected phones, etc.) without an operating system on them.
How to fix An operating system wasn’t found
- To solve the problem, first of all, I recommend disabling all external drives(USB flash drive, external hard drive, etc.) from your PC.
- Carefully check that the hard drive cables are securely connected to the motherboard, the cause of the problem may be the plug of the corresponding cable that has slightly moved away from the connector.
- Go to BIOS and make sure that the hard disk with the operating system is installed as the first one in the list of boot disks. If it is not in the BIOS settings, install it first in the sequence of rubble disks.
If you thoroughly checked your PC, did not find any connected flash drives, and the cables of the hard drive are tight, then to solve the problem “An operating system wasn’t found. Try disconnecting any drives that don’t ”we need a rubble flash drive (or DVD) with an operating system identical to the one installed on your PC.
Do the following (using Windows 10 as an example):
If the error persists, do the following:
Now, in accordance with the table of sections, we determine the method of correcting the problem.
If you have MBR
Suppose Windows OS is located on drive C. Now we enter the command in the command line to create boot files on this disk... We type:
bcdboot C: \ Windows / S C:
and press enter. The system should return you a message “Boot files successfully created”.
Now type diskpart again at the command line and hit enter.
Then enter list disk and press enter again.
Enter the command select disk 0 and press enter again (0 is the ordinal number of the disk that contains the operating system).
Then we enter the following commands, remembering to press "Enter" after each command:
list volume
select volume X (instead of X, enter the number of the partition on which the OS is installed, usually it has a label like "System reserved" (reserved by the system).
active
exit
Now close all windows and restart your computer by disconnecting external drives (USB flash drive or DVD). The problem can be solved and you can get rid of the "An operating system wasn't found" error on your computer.
If you have GPT
First, we need to determine on which disk the Windows OS is installed. Type dir c: on the command line and hit enter. If you see Windows among the list of directories, then the OS is located on this drive C. If Windows is not there, then enter dir d: and so on, until you find the drive on which your OS is located.
Suppose Windows OS is located on disk C. Now we enter the following in the command line, remembering to press enter after each command:
diskpart
list disk
select disk 0 (0 is the sequential disk number that contains the operating system)
list partition
See which partition is labeled "system". Select the system partition by typing:
select partition X - (replace X with the system partition number)
Assign a letter to the system partition using the command:
assign letter = S - (let it be the letter S)
Then type exit and press enter to exit the functionality of the diskpart command.
Now enter the following commands, remembering to hit enter after each one:
cd / d S: \ EFI \ Microsoft \ Boot \
ren BCD BCD.bak
bcdboot C: \ Windows / l ru-ru / s m: / f UEFI
After that, close all windows, and restart your computer, remembering to remove all external media (flash drive or DVD). The error can be corrected.
Conclusion
The cause of the error “An operating system wasn’t found. Try disconnecting any drives that don’t contain an operating system. Press Ctrl + Alt + Del to restart "may damage the system partition on which the loader is located, which is necessary to start and boot the OS correctly. Use the set of tips I have listed, this will help get rid of the "An operating system wasn’t found" error on your PC.
In contact with
Question: An operating system wasn "t found. Try disconnecting any drivers
So, I updated the laptop to 10, try it out, so to speak. It was 7. Completely lick, all the cases. I sat for 10 weeks, she got tired and decided to roll back. None system files did not touch. Everything was going fine, when suddenly a black screen and this error "An operating system wasn" t found. Try disconnecting any drivers ". With a proposal to press the holy trinity to reboot the system. When you reboot, the same screen pops up WITHOUT the opportunity to enter the BIOS. That is, a constantly black screen and this error.
Toshiba satellite c850 c3s laptop. 64 bits.
That just did not poke, at 0. Restarting and turning on a new one does not help. No start screen, just an error. So, how to enter BIOS in such a nasty situation?
I have been googling for not the first hour, but what they advised me does not help.
Answer: you still did not get into the BIOS, the question was about that. and the answer remains the same -
Message from qvad
no way, sew with the programmer
Question: Acer Aspire V3-571G - an operating system wasn "t found windows 10
In general, I installed on days windows 10 - everything is good.
After a while, I caught a spam virus and could not remove it in any way.
I decided to reinstall Windows again.
And somewhere at 30% reinstallation, the laptop froze and restarted.
When he turned on, the following message came out: an operating system wasn "t found.
Please tell me what to do? (BIOS turns on)
Added after 13 minutes
Here detailed description screen messages: An operating system wasn "t found. Try disconnecting any drivers that don" t contain an operating system.
Answer: Ivan_polovina, do you have a paid Google?
Question: An operating system wasn "t found after cleaning system unit
Good day to all.
Yesterday I decided to clean my computer from dust, I never cleaned it before. Disconnected all modules, connectors from the motherboard (I realized later that it was in vain), cleaned all the fans from dust, and when I started to connect everything back, difficulties arose (in where in general, what to connect). MSi Z77A-G43, I downloaded the manual for it, I connected it with great difficulty, in order to check the correctness of the connections, I decided not to close the lid, connect the power + display + mouse with keyboard, the result: the computer turned on as if nothing had happened, that is, went to the work the table (there was joy), but since I did not connect the Internet, the sound + the lid was not twisted from the system unit, I disconnected it from the power supply and began to tighten the bolts. But then the fun began., the computer did not turn on, although I only tightened the bolts + connected a couple of wires to the back panel. I sat until 5 in the morning, and I managed to turn on the computer, only it turns on with an error: An operating system wasn "t found. Try disconnecting any drivers that don" t contain an operating system.
I read topics with such an error on the forum, for most of them it pops up when the system is reinstalled. What should I do? Why did it turn on and after closing the lid did it stop turning on?
Answer: igorSmile, well, so he tried to boot from something where there is no Windows ... so he could not.
and you set it to boot from Windows and start
Question: Doesn't enter BIOS, Operating system not found
Hello, I studied the forum, but I could not find a solution. So here:
There is Acer Aspire V5 571g.
A couple of weeks after upgrading to Win 10 bsods began to fly out " system thread exception not handled" and " page fault in nonpaged area"Sometimes rebooting helped, sometimes just starting the kolobok and rebooting helped.
After another couple of weeks, the laptop stopped seeing bootable USB drive with a kolobok, in BIOS I put legacy - reboot - eSET LiveCD started.
Turn off the laptop, pulled out the USB flash drive, start it up, I want to enter BIOS as usual in order to switch to UEFI, but it won't let it go there. Writes " Media Test Failure, check cable"and then" operating system not found".
And so what I did to cure the laptop:
1) I rolled half a liter of strong.
2) I clicked all kinds of keyboard shortcuts to enter the BIOS.
3) Loaded from a USB flash drive with Windows to go into reboot in BIOS, but in the "diagnostics" item there are no UEFI software parameters.
4) "Shutdown.exe / r / o"via cmd does not work. cd c: \ does not work. As x: \ sources stood, so it is.
5) I looked at the possibility of reinstallation, the hard one is visible in the Windows installer.
6) When trying all kinds of restorations, writes that the HDD is locked and you need to unlock it.
7) Restoring the boot environment with BCDboot tried it.
8) I took out the battery for half an hour.
9) The "ON" button was pressed for a long time.
I have no idea what to do. Windu is not desirable to demolish. Foolishly left a bunch of things important on the HDD. The laptop is not under warranty.
Gentlemen, can anyone come across a successful treatment?
Answer: Okay, that's understandable. But is there an opportunity to somehow restore work? You just need to somehow get into the BIOS.
Added after 42 minutes
In short, it suddenly turned out to enter through Alt + F10. Transferred to UEFI, raised hard to priority and everything went well. But bsods still have a place to be. Experienced people say that the problem is with the video card. Unfortunately, reinstalling the firewood did not help. Whether it's a dozen or not, I don't know. I will demolish and install 8.1.
Added after 4 hours 17 minutes
New BSOD MEMORY MANAGEMENT and is not included in the BIOS)
Question: Samsung NP-R525 laptop repair. Operating System Not Found
We need your help, friends. Bought used Samsung laptop NP-R525 (Bremen DR2-1G BA41-01572A REV: 1.1). The problem with it was: periodically devices (hard disk, CD drive, USB-connectors) fell off. The system saw and did not see them. After examining the BIOSa of the device, an oddity was revealed - BIOS version was 00PC. I thought that the problem was buried here. I decided to flash FlashROM with a programmer (this experience is already available). I took it off the board and connected it to my computer. Problems started. FlashROM is not detected by the flasher. Writes unknown manufacturer, unknown chip. Having rummaged a little on the Internet in search of a solution to this problem, I scored on flashing with a programmer. I decided to do it from under DOS. But having put the chip in place, I ran into a new problem. Now, when booting, the laptop instantly displays a black screen with the inscription "Operating System Not Found". No bootable Samsung screens before that, no, just a black screen and an inscription. Accordingly, there is no entry in the BIOS. Connected / disconnected hard. I rearranged the memory cards for everyone, put others. Without changes. I found an absolutely similar mother. I removed the chip from there and put it on the subject to be treated. The same thing ... (What can be, where to look? Do not judge strictly for my hasty conclusions and mistakes in actions, I am just learning and I took this device purely for experimental purposes.
Answer: ir station
Added after 27 seconds
if there is an understanding of the process - two spotlights
Question: Acer aspire V-5-571 "operating system not found" at boot
Friends, help to solve the problem, installed windows 7 on laptop acer aspire V-5-571, during the installation of Windows from a USB flash drive, when choosing a railway partition, deleted all partitions, created one clean partition. After copying the installation files, the installer rebooted the computer and a sign popped up: "operating system not found" It does not allow to enter the BIOS, the laptop does not respond to any commands, Windows is not installed
Answer: zohan0290, throw off the screw, go to BIOS and put everything you need. This is me about the secure boot.
Message from qvad
hard hybrid
The system is somehow purple, for it the flash part of the screw is a cache of the second level.
Question: Winlocker uninstalled windows - Operating System not found
Hello everyone, by a stupid accident I fell for a winlocker that threatened uninstall windows, as a result, the virus did not bluff =)
When you turn on the computer, it gives an error: Operating System not found.
What to do?
Here is such a message I appear when I turn on the laptop.
It turns out to enter the BIOS, the first boot place is hard - everything is fine here.
What else does he want?
Answer: There was the same error, the reinstallation helped different vindovos, the diagnostics showed that everything was fine with the screw, but later on the problems began to freeze when loading the vidvos on the splash screen, in the end I bought new hard disk, no more problems, so think about it.
