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5 Perfect Solutions to Getting Missing Operating System Back

  • Contents:

    Brief Introduction to Missing Operating System Error

    When you tried to start a Windows operating system, you may receive the error message Missing Operating System on the black screen. That’s a so annoying error since it will prevent you from entering Windows. Well then, what’s the cause for this error and how can we get missing operating system back? These are what we are going to talk in this post.

    Tip: depending on the BIOS used by system, the error message could also be Operating System not Found.

    BIOS doesn't detect hard drive
    BIOS doesn't detect hard drive

    The Following 5 Issues Can Cause Operating System Missing

    Both hardware issues and software failures can make an operating system not found, and here we mainly list the following 5:
    1.The basic input/output system (BIOS) does not detect the hard disk that installs Windows.
    2.The hard disk failed either physically or logically.
    3.Users make inappropriate or incorrect BIOS settings.
    4.Windows Master Boot Record (MBR) located on the hard drive is damaged or corrupted.
    5.The partition which saves Windows boot files is no longer active or users set wrong partition active.

    As long as one or some of these 5 issues are generated, users may receive the disturbing error message Missing Operating System or Operating System not Found. But fortunately, for each cause we have solution. Let’s see details.

    The Following 5 Resolutions May Help You Get out of Missing Operating System Error

    Since multiple issues can lead to the error, most users do not know how to start the repair. Actually, they had better start with checking hard drive for hardware failures and then deal with software issues since the latter should be done on the base of correct hardware condition. And the following 5 solutions are introduced in this order.

    PS. This is just a personal idea, and you can choose one of our methods depending on your actual situation.

    1.Check If Hard Drive Is Detected by BIOS

    If the system disk isn’t recognized by BIOS, it cannot be used to read and write data. As a result, all files including Windows OS saved on the disk will be inaccessible. If you made dust clean or your computer suffered heavy shock before the Operating System not Found error appears, it is very necessary to check whether the hard disk has been detected. Detailed steps are as follows:
    • Start computer and press a specified key to enter BIOS(Usually it is F2, F10, Del…). However, different computer or motherboard requires different key, so you can search on the internet or consult your manufacturer to get the correct key.

    • In BIOS please find these or similar items: IDE Primary Master, IDE Primary Slave, IDE Secondary Master, etc.

      BIOS doesn't detect hard drive

    • If no disk is shown up or system disk isn’t here (shown as None), we can say BIOS doesn’t detect the drive. Tip: sometimes it may be shown as Not Detected rather than None. When hard drive isn’t detected, different users should take different measures.

      If you are capable of taking out hard disk and then connecting it correctly, please quit from BIOS and power off computer. Then, take apart computer and reconnect hard disk steadily. Supposing the Missing Operating System error appears due to unsteady connection, the hard disk would appear in BIOS again after reconnection:

      BIOS detect hard drive

      And then Windows might be bootable after we quit from BIOS.

      Tip: if you are unclear of internal structure of computer, please do not operate at random, because even a slight mistake may cause more serious damage. And you’d better ask others for help.

      But sometimes the target hard disk is still invisible even if we have done reconnection, and there are 2 possible reasons: the interface for the drive is forbidden; the hard disk has been damaged seriously.

      enable interface in BIOS

      To deal with this kind of situations, please highlight the option for the hard drive and press on Enter. Then choose Auto when there is such an option. If the hard drive is also invisible in BIOS after we selected Auto, it may have serious problems, and you’d better send it to repair or for replacement.

      Nevertheless, even if the hard disk has been detected by BIOS, we may get 2 different results: Windows starts successfully; Windows is still unbootable. If you get the second result unfortunately, please test hard disk to see whether it has failures.

      Tip: if you are afraid of losing important files during hard drive test, it is possible to transfer these files out in advance. MiniTool Power Data Recovery Bootable edition is a piece of bootable data recovery software that can recover data without loading Windows, and its Damaged Partition Recovery module will help you transfer data out from an existing partition. For more information about this program, please see Power Data Recovery Boot Disk.

    2.Test Hard Disk to See Whether It Failed or Not

    On some types of motherboards, hard drive diagnostic tools are added to help users test hard disk for errors, and you can enter BIOS to see whether there is such a tool on your motherboard. As to how to enter BIOS, we have said in solution 1.

    I have a HP laptop which is with such a utility:

    hp hard drive selft test tool

    Primary Hard Disk Self Test under Diagnostics is the very tool I can use to make a test. If you do not know how to use your diagnostic tool, please view your computer or motherboard manufacturer’s website to find specific operations.

    If any test fails, users can contact their hard disk or computer manufacturers for a replacement as long as these devices are under warranty. However, in order to avoid data loss and privacy leakage, users need to do the following 2 operations before the replacement if their hard drive is still functional: transfer all important and private data out to make a backup; erase source data to avoid privacy leakage.

    Both operations can be done in either failed computer or another computer. If you have a bootable computer available and know how to connect the failed drive to the bootable computer as a slave drive, just backup desired data and erase source data on another computer. If any of the 2 conditions cannot be met, you’d better perform these operations: download a bootable data recovery software to transfer needed data out, which has been introduced in solution 1, and then employ a bootable partitioning program to erase source data. MiniTool Partition Wizard Bootable CD (freeware) can help do the erase via wiping partition or disk.

    Steps to Wipe Disk or Partition

    Firstly, please download MiniTool Partition Wizard Bootable CD, which is an ISO file, and then burn it to CD, DVD, or USB flash drive. Then, boot computer via the bootable disc to get the window below:
    Download Now
    Tip: This article tells how to build Free Bootable Partition Manager with Pwfree91.iso, follow the steps to create your own one.

    wipe partition in partition wizard

    Here all disks and partitions are shown clearly. To wipe a partition, please select the target partition and choose “Wipe Partition” feature from the left side. To wipe a disk, select the target disk and choose “Wipe Disk”. Then, choose a wiping method and click “OK”. At last, click “Apply” button to make all changes applied.

    Nevertheless, if all tests pass, we guess the Missing Operating System error might be caused by software failures, and users can try taking the third solution.

    3.Set BIOS to Default State

    Sometimes doing wrong or inappropriate BIOS settings may make operating system not found. If no error is found during hard disk test, try to set BIOS to default state, which may solve your problem. Detailed steps are as follows:

    • Restart computer and enter BIOS.

      load optimal defaults in BIOS

    • Find and enable the default setup option, which could be Load Optimal Defaults, Get Default Values, Load Optimized Defaults, Load Setup Defaults, and so on.
    • Press on F10 to save changes and quite from BIOS.

    However, if this method doesn’t solve your problem, your hard drive’s MBR may have been damaged.

    4.Rebuild Master Boot Record

    Both mistaken operation and virus attack may cause MBR damaged. Once this special boot code (located in the first sector of a hard disk) is damaged, Windows won’t start. Well then, how can we fix or rebuild MBR without loading system? Users can turn to these 3 tools: Windows installation CD/DVD, Windows repair disk, and MiniTool Partition Wizard Bootable CD (a freeware for Windows non-server users).

    Rebuild MBR with Windows Installation Disk or Repair Disk

    If you are using Windows installation disk, start computer with it to get Language select interface, then make preferences, and click “Next” to continue.

    repair computer in windows installation disk

    Then, choose “Repair your computer”. Next, select a system to repair and click “Next>” to get multiple recovery tools:

    recovery tools in windows installation disk

    Here, we can choose either Startup Repair and Command Prompt to do the recovery. However, since the former will automatically fix all problems that are preventing Windows from starting, it will require much more time. So here we just choose Command Prompt to open a command prompt window:

    repair mbr in command prompt of windows installation disk

    In the window above we can type bootrec /fixmbr to fix MBR only, but we can also type bootrec /fixboot and bootrec /rebuildbcd to do more repairs. At last, safely quit from Command Prompt by typing exit.

    Tip: since steps to fix MBR by using Windows repair disk are nearly the same as those by using installation disk, here we don’t introduce this program.

    After these operations, you can restart computer to see whether the problem has been solved. Nevertheless, Microsoft says the fixmbr command may damage your partition table if a virus is present or if a hardware problem exists. Once partition table is damaged, existing partitions might be inaccessible so that data cannot be used. Well, is there a much safer way? Actually, MiniTool Partition Wizard Bootable CD can help rebuild MBR without bringing any damage to data and partition since it operates the master boot record only. For detailed steps, please see Rebuild MBR.

    However, if fixing MBR still doesn’t work, users need to try our last solution.

    5.Set Correct Partition Active

    If we are running Windows under Legacy BIOS + MBR mode, the partition which saves boot files should be set active so that MBR can pass boot right to boot manager which is in charging of finding Windows. For more details of Active Partition, please see Accidentally Marked Drive C Active. If a wrong partition is set active, naturally operating system cannot be found. But fortunately, users can start computer via bootable partitioning tool to see whether their active partition is set correctly, and then set the wrong partition inactive and mark right partition active. MiniTool Partition Wizard Bootable CD can help do these operations. Detailed steps are as follows:
    Download Now

    Firstly, boot computer with MiniTool Partition Wizard boot disc to get the following window:

    set active partition in partition wizard

    In Partition Wizard the partition which is marked as Boot should be set active. If there is no active partition, please set this partition active. However, if a partition is set active mistakenly, please set the wrong partition inactive at first, and then set the correct partition active. Finally, click “Apply” button to make all changes performed.

    For detailed steps, please see Set Partition Active/Inactive. Once all changes are completed, try booting Windows from local hard drive.

    Now, all solutions to Missing Operating System or Operating System not Found error have been shown, and you can try using these solutions when troubled by such a kind of questions. If one or some of these resolutions are proved to be useful for you, cplease share this post with others who have similar troubles. However, if all these solutions do not work to your situation, the problem could be quite serious, and you may need to reinstall Windows or contact your computer manufacturer or hard disk manufacturer for further assistance.

    "These five solutions to Missing Operating System & Operating System Not Found prove to be useful, and I guess they are also useful to your buddies who are suffering from this issue…"

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    Tip: if you plan to reinstall Windows but fear of losing desktop files as well as data saved in User documents, try using Power Data Recovery Bootable Edition mentioned in solution 1 to transfer needed data out before reinstallation.