Aug 20, 2009
My Digital Life Editorial Team

Hack to Remove 100 MB System Reserved Partition When Installing Windows 7

On a fresh (custom) installation of Windows 7, where Windows 7 is installed onto a new hard disk with unallocated disk space (no partition or volume been defined yet), or when user attempts to create a new partition out of empty drive, the Windows 7 installer will create an additional partition with the size of 100.00 MB, and mark as System Reserved.

The 100MB volume is labeled as System Reserved with NTFS file system, and System, Active, Primary partition attribute with no drive letter in Disk Management. The 100MB system reserved partition is only available for Windows 7 Ultimate, Windows 7 Business and Windows 7 Enterprise editions. The 100 MB system partition is used primarily as BitLocker partition for BitLocker encryption. Additionally, it also holds the Windows Recovery Environment (WinRE) and boot files with boot manager for booting up the computer for troubleshooting when there is no Windows 7 installation DVD disc on hand.

The Windows 7 created 100 MB partition is not the main boot partition or boot drive, but serve only as a backup. The following files and folders are the initial content of the partition (names in [] brackets indicate it’s a folder or directory), before BitLocker is enabled and in use.

Windows 7 System Reserved 100 MB Partition

[$RECYCLE.BIN] [Boot] [System Volume Information] bootmgr
BOOTSECT.BAK

For Windows 7 users who do not intend to use BitLocker, the 100 MB partition can be removed subsequently and easily in Disk Management, the built-in partition manager of Windows 7. However, users can stop and prevent the 100MB partition from been created in the first place during installation of Windows 7, via several workarounds and tricks or hacks. These hacks have slightly different from trick used to remove 200 MB partition in Windows 7 RC or Beta.

Method 1: Use Existing Partition or Partitioning Scheme

Windows 7 installation wizard will not modify existing partition which already been defined and allocated. The 100 MB BitLocker partiton will only be created when user creates new partition on a clean and empty HDD (no partitions), or delete all partitions and then create a new partition during setup. Thus, system with hard disk already partitioned, and users wish no change to existing partitioning but wish to clean install can just format the partition in Windows 7 setup wizard before installing.

Method 2: Partition the HDD Before Installing Windows 7

It’s “almost impossible” to stop or cancel the 100MB system reserved partition from been created in Windows 7 Setup (unless you uses hack 3 below). So for people you prefer to delete off all existing partitions, or want to install Windows 7 to an empty hard disk, it’s recommended to partition the hard disk before starting Windows 7 setup, through several ways.

One way is to boot up the computer with a Windows XP or Windows Vista installation CD or DVD, or any other bootable disc with disk partitioning utility, and then perform the re-partitioning. Quit the setup after finished partitioning, and start up the computer with Windows 7 DVD to install Windows 7.

For user with only Windows 7 DVD, follow these steps, as provided by UkonCornelias:

  1. Once Windows 7 Setup is loaded, press Shirt + F10 keys at the first setup screen (which allows selection of language, keyboard and locale). A Command Prompt window will be opened.
  2. Run Diskpart, the built-in disk partitioning tool of Windows 7 with the following command:

    diskpart

  3. Type in the following command one by one, follow by Enter key to create a partition (text in brackets are comments only):

    list disk (to show the ID number of the hard disk to partition, normally is Disk 0)
    select disk 0 (change 0 to another number if applicable)
    clean
    create partition primary size=80000 (create a partition with 80 GB space; to use entire disk as one partition, omit the “size=value” parameter switch; use similar command to create more partition if needed or create in Windows 7 after installation)
    select partition 1
    active
    format fs=ntfs quick
    exit

  4. Type exit at command prompt to close Command Prompt window.
  5. Continue Windows 7 installation as usual. Remember to just highlight and select the partition just created when come to partition screen.

Method 3: Trick to Remove 100.00 MB System Reserved Partition During Setup

  1. On the “Where do you want to install Windows?” partition screen of Windows 7 Setup, click on Drive options (advanced) to delete existing partitions and create a new partition.
  2. Click OK when Install Windows wizard prompts with the following message:

    To ensure that all Windows features work correctly, Windows might create additional partitions for system files.

    Additional Partition in Windows 7

  3. Two partitions should be created, a System Reserved System type partition (Disk 0 Partition 1) with 100.00 MB in size, and originally intended primary type partition (Disk 0 Partition 2) with allocated size now less 100MB.
  4. Delete the Primary Partition created.

    Delete Primary Partition in Windows 7 Setup

  5. Click OK when prompted that “The partition might contain recovery files, system files, or important software from your computer manufacturer. If you delete this partition, any data stored on it will be lost.”

    Confirm Partition Delete

  6. All disk space inside the partition deleted will now become unallocated space. Now, highlight System Reserved Partition, and click Extend. Assign the available disk space to the partition, and click Apply.

    Extend Partiton Size in Windows 7 Setup

  7. Click OK when promoted with “Extending a partition is not a reversible action. If you proceed, you will not be able to undo this action later.

    Extend Partition in Windows 7 Setup

  8. Highlight on the extended System Reserved Partition, and click Format.
  9. Click OK when prompted with “The partition might contain recovery files, system files, or important software from your computer manufacturer. If you format this partition, any data stored on it will be lost.”

    Format Partition in Windows 7

  10. After finished formatting, the originally System Reserved Partition will now become normal system partition, ready to install Windows 7. Proceed to install Windows 7 as usual.

    Windows 7 Partition Selection

Note: If you plan to create more than one partitions, all partitions should be created first before deleting one that intended to be used as Windows 7 partition.

More hacks and usage guides of Windows 7 is available.

  • CarolC

    > press Shirt + F10 keys

    Where is the “shirt” key?

    (And does anyone ever proofread anything on myDigitalLife????)

    • gaberilde

      its meant to say shift key

  • Neil

    I don’t know how a simple explanation can create so many queries…? The object of this exercise is to STOP Win 7 from creating an unwanted partition – THAT IS ALL. Everything else you want to do – you do LATER…after you have installed Win 7 (by using disk management tools, perhaps).

    I wanted to get rid of this partition for security reasons – so I fist of all securely deleted the entire hard drive (using a Jetico product – excellent and trusted by me for over a decade).

    Now, having a securely clean hard drive, I DO NOT want to trust Windows to help me delete the partition AFTER its creation..so I want to STOP it being created in the first place. Method 3 by UkonCornelias above is the way to do this. Do not do anything else except this method – simple.

    When using the method of Ukon, press SHIFT+F10 and follow his guide. Remember that on a single disk setup, Disk 0 is your BASE disk – the physical object fitted into your computer case. You then create a PRIMARY partition using his guide, remembering that 1 Gigabyte is 1024 Megabytes – so to customise your PRIMARY partition size, multiply 1024 by whatever Gigabyte size you want it to be – I wanted a 50GB PRIMARY partition for Win 7 Ultimate so 1024 x 50 = 51200 and don’t type any units, just the number. So using his guide, I typed …size=51200

    Doing this, I had a PRIMARY partition which the program DiskPart named 0 – so I now had PRIMARY partition 0 sitting ‘on top of’ the actual physical Disk 0. Think layers, like a cake. Make sure you mark as ACTIVE and then FORMAT this PRIMARY partition before (re-)selecting disk 0 again to take you back to the base physical disk.

    Now I had a large physical disk with a formatted PRIMARY 50GB partition and the rest of the hard disk was UNFORMATTED. To stop any risk of Win 7 trying to put the unwanted 100MB partition on the UNformatted section, I again followed the basics of Ukon’s instruction. I now created an EXTENDED partition in the remaining space.

    So as above, I had selected Disk 0 (the physical disk). Now type CREATE PARTITION EXTENDED and press enter. Do not use the word ‘size’ at all. By not specifying a size, DiskPart now uses the REMAINING free space to create the extended partition, thus denying Win 7 anywhere to create its unwanted 100MB partition. Remember, you can tweak the extended partition later using disk management tools – this exercise is JUST to stop the creation of the unwanted 100MB partition. This extended partition is named PARTITION 1. Select it, format it per the above and exit.

    You now have your whole harddrive divided into primary and extended partitions, both formatted – thus denying Win 7 the opportunity to create unwanted partitions and by not doing this through Windows, preserving the integrity of the previously securely deleted hard drive.

    There is nothing different in here to Method 3, just another way of saying it to the confused (as I was, initially, until I poked and prodded).

  • juan

    And how can I create it again? (without reinstalling Windows)
    I mean, with any 3rd party application I can create partitions, primary, extended… but I cannot find the way to convert unallocated space to this special recovery partition.

    I got to install Windows 7 on an external USB drive but only to a primary partition. I can’t get that 100MB rescue area from unallocated space.

    regards

  • egg

    Why would I press my shirt and f10?

  • Farhan

    You made my day man……I was getting an error due to the incorrect partitioning i did. Thanks alot.

    • Ryan A. Naylor

      What kind of error?

  • Kevin Still

    So, I didn’t use to have this…

    I was messing around with a Windows 7 disc (while on my desktop) and I clicked install windows, I was trying to see what version of windows was on it… and then it started copying files so I canceled it. But now I see this dumb 100mb drive. which was never there… so since I never had it/used it to begin with can I delete it? or some how hide it.. its taking a drive letter I use for other things.

  • alexanderpas

    Hack 4: (adaptation of hack 3)

    – Create partition
    – 100MB disk appears
    – Delete 100 MB disk
    – Create new Partition 1
    – Remove Partition 2
    – Extend Partition 1

    • CarolC

      But how do you delete the 100mb partition?
      The DELETE button is ghosted whenever you select it.

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  • Mark_M

    I too am looking to eradiate the 100MB partition creatred by a Win 7 Home Prem Upgd install. I dont care about the space (on a 1TB HD), but it impacts the nature of my backup strategy. I keep OS and PGMs on C, and rest of HD is data. This way, I can create a “golden” OS image, on and off HD for restore if needed. The addition of a funky ‘extra’ partition, with files reqd to boot, doubles the ‘things’ needed to backup and synchronize.

    Best path, Pre-format a C boot partition before, or during install, and avoid completely.

    Happy New Year!

  • ryan

    if the only reason to remove the 100mb partition is because its an eyesore, you can hide the partition. then you can still have it as a ‘just in case my computer crashes’ reserve.

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  • garria10

    Method three works – I was unable to use system restore or any imaging program, (I was getting, variously, error 0x80780119, 0x80780029 and 0x80070570) all tied into the Volume Shadow service which uses the system reserved partition. I tried several methods from other forums to increase the size of the 100MB partition, all of which failed. This does work, although I have spent all day reinstalling windows and all my apps…..

  • Swanidhi Singh

    I have a simpler solution.
    If you already have the crap partitions, you don't need – Follow your method (Shift + F10) and clean the disk. Now install fresh windows. If you don't ask for a partition during the time of installation, it doesnt create any 100mb parition for system. After the installation is done, you can shrink the partition and create another logical drive.
    Hope this helps.

    Swanidhi

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  • Lester

    Thanks for this! The extra partition was really an eyesore. If only I knew about it before my initial install

  • HomeP-User

    "The 100MB system reserved partition is only available for Windows 7 Ultimate, Windows 7 Business and Windows 7 Enterprise editions"

    I have Home Premium, and I got the 100MB partition…?

    • John

      Useful page this, I also have Home Premium and get the annoying 100MB partition created on setup.

  • Tito

    Thank you so much!!!

  • Gregory

    Is there any easier way to merge boot and windows 7 partition into ONE AND ONLY partition?

    Is there any program that do all the procedure automatically?

  • dty1

    Quux, thank you very much indeed. Excellent instructions. I would add that you need to right mouse on the CMD (command prompt icon) and select Run As Administer. Much appreciated.

  • Barry

    Firstly, the System Reserved partition has absolutely NOTHING to do with BitLocker.

    Secondly, it is created on a raw HDD no matter which flavour of Windows 7 is being installed.

    Thirdly, from Microsoft ….

    "The 100MB partition is a system partition and contains boot files. Disk Manager will not allow you to remove this partition because removing this partition could cause the system to not boot"

  • Barry

    The System Reserved partition is created by ALL versions of Windows 7 on a raw hard drive.

    Note that it has absolutely nothing to do with BitLocker.

    "The 100MB partition is a system partition and contains boot files. Disk Manager will not allow you to remove this partition because removing this partition could cause the system to not boot."

    There is NO Boot folder let alone bootmgr or BOOTSECT.BAK on my boot drive. I installed Windows 7 Professional onto a raw HDD.

    .

  • saunataga

    The 100MB partition is created in WIN 7 Pro, which replaces Business. The business name was scrapped. BitLocker is not included in Pro.

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  • Mark Wharton

    Your statement that the Windows Recovery Environment (WinRE) is stored on the 100 MB System Reserved partition is incorrect. WinRE files are stored in a folder named "Recovery" on the main Windows partition (C: for a standard installation). You can clearly see from your figure at the beginning of the article that there is no folder named "Recovery" in the list of files and folders on the System Reserved partition. This partition only stores the information needed to boot the PC.

  • Dennis

    There is an easier way to achieve Option 3.

    1) Delete all partitions (if there)
    2) Create a new partition of size 50Mb
    In this case only a single partition will be createdd
    3) Extend the 50MB primary partition to your desired size (or all disk space)
    4) Select the partition and continue install.

    Cheers..

  • chalaka

    U r a geniuos… wel done man..

    Thanks a lot

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  • belltown

    I plan to use Method 3 to remove the System partition. Currently in Disk Management I see that SYSTEM is marked as "System, Active, Primary Partition" and C: is marked as "Boot, Page File, Crash Dump, Primary Partition". So if I delete the C partition and extend the SYSTEM partition, will the SYSTEM partition become "System, Boot, Active, Page File, Crash Dump, Primary Partition"?

  • kisianik

    to bob:

    I did exactly as you said – now I have dual boot of 2 choices: Windows 7 and Windows 7, both lead to the same Win7.

    how to get rid of Dual boot?

  • Jim

    Method 3 above worked a treat. Thanks Guys

  • TOERINGANDTHONG

    @ azuan THEN TRY METHOD 1 OR 3,,DUH !!!

  • azuan

    stuck at method 2…

  • bob

    In reply to Ken, you can remove the 100mb partition once windows is loaded, you just cant do anything with it because its at the beginning of the drive and therefore cant be exteneded:

    1) Open a command prompt with administrator privileges (right click => run as administrator)

    Type:

    bcdboot c:windows /s c:

    You should get a message similar to:

    Boot files successfully created.

    2) Open the Disk Management GUI (you could use diskpart for scripts), locate the C: partition right-click and select “Mark Partition as Active”, select yes to the “do you want to continue message”

    3) Reboot to confirm that everything is ok.

    4) In Disk Management you can now delete the 100Mb System Reserved partition by right clicking on it and selecting “Delete volume”

  • Alan

    2010/07/01 The method #3 is good.

  • Martin Gee

    That was a nice little trick expanding that silly old 100 mb portition. Now it can be as big as it hoped to when it first was partitioned. ๐Ÿ™‚

  • Stefanus

    Hello , i have just read your article , i have a question . Right now i want to remove my second hdd but when i turn on the computer , it said "NTLDR was missing". But if i put my second hdd to the computer, Windows work properly. I think my problem is related to your article. Can you help me ? ๐Ÿ™‚

  • Carlos

    Thanks.! I worked really well. Orale

  • Juggler

    another way if you plan on have multiple partitions is to "juggle" them a little

    make partition 1 50% of hdd then you have

    1 100mb system

    2 30gb partition

    delete the 100mb and make second partition on the other 50% and then you have

    1 100mb unalocated

    2 30gb partition

    3 100mb system

    4 30gb partition

    delete partition 2 and create a new one using 100% of the free space and you have

    1 30.1gb partition

    2 100mb system

    3 30bg partition

    delete partitions 2 and 3 ๐Ÿ™‚

    create your second partition in windows after you have installed

    that is as far as I tested as I used this method to create an aligned partition on a SSD for Win XP

  • Sylvia

    Is that the typical post soviet twattiness rearing its head, along with the inability to understand the importance of definite and indefinite articles…silly to write a guide if you just throw out anyone who doesn't know as much as you do. Why write a guide if everyone is on equal terms?

  • Ken

    You state:

    "For Windows 7 users who do not intend to use BitLocker, the 100 MB partition can be removed subsequently and easily in Disk Management, the built-in partition manager of Windows 7."

    This cannot be done, since the System Reserved 100 mb partition is the System AND Active partition. The option to delete this partition is greyed out in Disk Management, since you can delete neither of the types it is (System or Active).

    Other methods described here to prevent it from being created work well. Thanks for the good info.

  • windowzHater

    easy as pie. to any of you that have problems, i am doing a fresh install, on a blank hdd.

    USE METHOD #3

    when it creates the "hidden" drive, it makes it the bootable system drive (primary), then creates another partition for everything else. all you're doing is deleting the extra partition, freeing up that space, then EXTENDING the system partition using that free space. if this is not working for you, take a break then come back in about 20 minutes and start over. as much as everyone hates to admit it, user error is usually the problem.

  • Irha

    Never mind… though it was not listed, it did get created. I reinstalled using the method 2 and confirmed that the reserved partition is not created. Thanks for creating this guide.

  • Irha

    When setup asks "To ensure that all Windows features work correctly, Windows might create additional partitions for system files." why can't you click "Cancel"? I hit Cancel and I didn't see any reserved partition created. In case it matters, this is what I did:

    – On a fresh drive, I chose to create a 50gb partition for win7 followed by a second partition for the rest.

    – I then removed the first two paritions (the reserved one and 50gb) and created new partition expecting that the reserved partition will no longer be created.

    – When I clicked on New, I got the above prompt for which I clicked Cancel. The result is that I didn't see there was no longer a reserved partition.

    I wonder if you can hit Cancel the first time itself and get away with this partition.

  • Irha

    When setup asks "To ensure that all Windows features work correctly, Windows might create additional partitions for system files." why can't you click "Cancel"? I hit Cancel and I didn't see any reserved partition created.

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  • Thanks a lot; it worked exactly as you said it would. It's stupid that they force this partition on the user; I don't intend to use 7 as my primary OS so it's annoying to have extraneous partitions.

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  • You can remove this partition AFTER install.

    1. Open CMD
    2. Type DISKPART (enter).
    3. Type LIST DISK (enter).
    4. Choose the disk that contains your WinRE partition. If it is disk zero, you type SELECT DISK 0.
    5. Type LIST PARTITION.
    6. Select the 100MB (or 200MB, depending) partition. If it were partition 1, you would type SELECT PARTITION 1 (enter).
    7. Type DETAIL PARTITION. Examine details to make sure this is the 100/200MB WinRE partition.
    8. Type INACTIVE to make this no longer the active, bootable partition.
    9. Now select your Windows disk – the one you want to boot from. If it is partition 2, you’ll type SELECT PARTITION 2.
    10. Again examine details with DETAIL PARTITION.
    11. Once you’re sure, mark it active with the command ACTIVE.
    12. Type EXIT to get out of Diskpart. You’re back at the commandline.
    13. You need to be sure there are system files on the new bootloader drive. if that drive is C:, you will put them there with this command: BCDBOOT c:windows /s C: (you can use BCDBOOT /? to learn the other options available.)
    14. Now reboot the machine.
    15. When it comes back, use Disk Manager to delete the old 100/200MB partition. You’re done, though I recommend a reboot to test.

  • echedey

    Thanks a lot! I was wondering what the hell was that of a system reserved partition when I was about to install W7 in a new disk.

  • Nick Marchini

    it's only 100MB so why mess around and delete it. It won't make much difference to the overall performance of the system!!

  • I had the same problem and did almost the same.

    Installing to a new (clean) HD I let the system partition everything but then deleted the 100MB partition reserved for systemfiles from the installer.

    It installed everything to the second partition.

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  • Happy User

    I love this! Yes works great for me on all my systems, I've been installing without the 100MB System partition ever since beta versions came out using this above method. Bitlocker serves only IT departments anyway. As Bitlocker will ultimately reduce system performance there really is no need for it in a standard user or enthusiast's performance environment.

    Especially since Microsoft did not give the customer a choice I say Stick it to the man!!

    Note to the OP: Do not use WinXP to create a formatted partition EVER!! WinXP does not respect partition alignment. Instead use a a Vista install disk or one of the methods described above..

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  • hithere

    1. Create a 50 MB partition.

    2. Click on the partition, click the Extend button, extend the partition to use however much of the disk that you want the first partition to use.

    3. Repeat steps 1 & 2 until you have your hard disk setup the way you want it.

    4. Be thankful it's really that easy.

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  • cereeee

    Little update.

    Microsoft is tricky. I thought that all was okay, so I deleted the partition on the 2nd disk.

    Reboot and boom, boot corrupted.

    I have disabled the 2nd drive in the bios before the repair to be sure that it won't recreate it on the 2nd disk.

    I repaired the boot with win7 dvd and all is okay now.

    I think that a file has not been copied when I did the copy on linux.

  • cereeee

    Hi everyone,

    First sorry for my bad english.

    Second : You may already have this problem, you have two clean hardisk and then you install win7, it create you the hidden System reserved partition in the second disk (ye it's true). Then you cannot format the second disk or your boot is corrupted.

    I found how to move this hidden partition into the first disk.

    First thing to do is to create a 100mb active partition named System Reserved on the first disk (I had luck because I had 1Gb free on my disk).

    Second thing is to boot with something like a linux live cd (like ubuntu).

    Third thing is to mount the original System Reserved partition into your linux and you mount the future System Reserved part., you copy all files and it's done, you can now boot on your first disk without have to boot on the second (and remove it, also).

    I hope my explaination were understandable.

    You can rewrite this tip for better english.

    Have a nice day!

  • Donald

    Hi

    I've just the opposite problem!

    I've installed Windows 7 rtm ultimate on my pc and all is perfectly working, but when I've changed My hdd IDE into another HDD S-Ata, I cannot succeed in creating 'hidden' partition of 100Mb, while I want to create it!

    How can I do in order to create this partition on my Sata HDD

    Regards

    Donald

  • harry

    "Did the poster actually try this before posting this article?"

    There is often information posted here that is questionable (to be diplomatic about it.)

  • snaphat

    B0r1s, did you not read what I said? I implied that the 100MB partition may well be the primary partition and that this guide may well be incorrect in stating that it is a backup and that it can safely be deleted once it exists.

    I mean, every single softmod crack for ultimate needs to assign that 100mb partition a drive letter and modify the boot partition on it to start a modified version of grub that bootstraps windows 7. In addition to that C: does not contain any boot manager files on ultimate. Now unless MS has changed how windows ultimate boots since the RC, and as far as I can tell they have not – I am saying it is not safe to delete the partition via the disk manager and that it will cause windows to be nonbootable. Did the poster actually try this before posting this article?

    Do not insult me by assuming I'm some ignorant ass who hum-drum decided to innocently ask a question because I was afraid my windows would become unbootable.

  • b0r1s

    snaphat, in a case of boot failure, if you don't know how to recover a boot sector using Win7 install disk then this guide was not for you.

  • snaphat

    Are you sure this partition can be deleted? Are you sure it is not the primary? I've read stories of people who deleted it and could no longer boot windows 7.

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