Windows 7 System Reserved Partition (100mb) problems when replacing boot disk


  • I recently purchased a new PC with 4 SATA 2 Terrabyte hard disks. I installed Windows 7 Ultimate and booted up with no problems. After a week I decided that I did not like the idea of booting from one of the four 2 terrabyte Hard Disks. I decided to add another smaller hard disk and boot from that leaving the other four hard disks free to fill up with data. This way I would have one small HD to boot with and the other four large HD for data, thus keeping the operating system separate from my data disks.
    I added another smaller 400GB hard disk with the intention of making the PC boot from the 400GB hard disk. I installed Windows 7 Ultimate to this HD and booted up without problems. So I have one 400GB HD to boot up and four 2TB HD for data. When all 5 disks are connected to the motherboard via SATA cables, the PC boots without problems.
    However, if I disconnect the four 2TB hard disks and boot up the PC with just the one 400GB hard disk, I cannot boot the PC and get an error message on boot up saying BOTMNGR IS MISSING, press control Alt Del to restart. If I reconnect the four 2TB HD, the PC boots up OK. So I have a situation where I can boot the PC when all 5 disks are connected, but I cannot boot if the four 2TB hard disks are disconnected. In computer management, disk management, I can see all 5 hard disks but one of the four 2TB hard disks has a 100MB system reserved partition which is hidden. I suspect that the reason the PC will not boot without the four 2TB disks connected is that this reserved partition is used during boot up. My question is why is the hidden partition on a separate hard disk, should it not have been installed on the same hard disk that I boot off. If for any reason the 2TB HD with the reserved partition should fail, then my PC will not be able to boot. The whole reason of using one disk to boot up with and the other disks for data becomes flawed as I will be relying on two physical hard disks to boot up intead of just one - the one with the operating system on it. Can anybody help me to configure my PC so that both the operating system AND the 100MB reserved partition reside on the same physical disk. I know this sounds complicated but I would really appreciate it if someone who has gone through the same process can give point me to some kind of a solution. Thanks.   
    Wednesday, March 03, 2010 8:05 AM


  • Hi Anthony,

    It's not such a big problem.

    Windows 7 introduced a new standard of booting. The small, essential amount of boot information is booted from the small partition that is hidden during normal work. The rest of the operating system is booted from your "Windows" partition. This offers some benefits like Bitlocker and Recovery environment.

    However, you are still able to boot with only one, "big", "Windows" partition.

    1. Boot normally with all your disks connected.
    In your search box type
    Navigate to your "Windows" system partition.
    Right click partition and "Mark partition as active".

    2. Prepare your Windows 7 instalaltion boot DVD.
    Shut down your computer.

    You must be carefull how you arrange your disks physicaly. Your boot disk should be the first disk detected by your BIOS.

    During boot repair phase, I would keep only the system disk connected and powered on and all the remaining drives disconnected and powered off.

    3. Power on your computer and boot it from the Windows 7 installation DVD (you may need to adjust your BIOS settings to be able to boot from DVD).

    4. On the "Install Windows", enter your language preferences.

    5. On the next window, click Repair your computer.

    6. On "System Recovery Options", make sure that "Use recovery tools..." is selected. Click Next

    7. There may be an interval where the wizard will try to repair your system. Finaly, "System Recovery Options" should present a list of options. Choose Command Prompt

    8. Run following three commands:
       Bootrec /FixMBR
       Bootrec /FixBoot
       Bootrec /RebuildBCD

    9. Rebbot your system.

    10. If the boot is successfull, power off your computer, reconnect all your drives and power up your computer again. You may then delete your old "small" 100 MB system partition. 

    Wednesday, March 03, 2010 9:29 AM