Windows 7 Forums

Welcome to Windows 7 Forums. Our forum is dedicated to helping you find support and solutions for any problems regarding your Windows 7 PC be it Dell, HP, Acer, Asus or a custom build. We also provide an extensive Windows 7 tutorial section that covers a wide range of tips and tricks.

Windows 7: How do I re-create the 100mb partition?

03 Dec 2010   #1

Windows 7 Ultimate 32 bit
How do I re-create the 100mb partition?

Hello guys, I'm new to this forum.

I need your help desperately:

I had system file corruption and had to reinstall Win7. The problem is that I formatted the 100mb partition.

I know this is an important part of the system and want to have it back. It complies with size (100mb) and position requirements (the first partition).

There are a lot of post dealing with getting rid of it. I want the opposite. Howw do I do it?

Now, there are some constraints: I cannot delete the entire disk because I have a Linux installation in another partition. And if I delete the 100mb partition to try and lure Win7 into creating it, it'll change the partition table and my bootloader won't be able to locate Linux.

Can you help me please.

My System SpecsSystem Spec

03 Dec 2010   #2


Be aware that having GRUB on the HD can corrupt Win7 at any point so this may not work although it is proven to create the SysReserved partition by tests done by BareFootKid and has worked for others:

Boot the Win7 DVD Repair Console or Repair CD, access a Command line to mark the 100mb partition Active: Partition - Mark as Active

Now boot the DVD repair console or Repair CD, accept any offered repair. When Win7 doesn't start, boot back in, click through to Recovery Tools list to run Startup Repair up to 3 separate times with reboots until Win7 starts. Startup Repair - Run 3 Separate Times

If this fails you can try doing a partition-specific wipe of 100mb, in case it has been corrupted by GRUB, using free Partition Wizard bootable CD which can also Modify>Set as Active. Then run Repair x3. You can also use PW CD to shrink Win7 to create the 100mb if it isn't already created as it appears from your post.

If it won't work then it is likely because of GRUB corruption on the HD, which is why it is best to Dual Boot Linux on another HD via the BIOS to avoid GRUB corruption of Win7.
My System SpecsSystem Spec
03 Dec 2010   #3

Windows 7 Ultimate 32 bit

I have deleted grub for now. So I don't think it will interfere.

Can you elaborate a little bit on that one? How does it Break Windows 7?

I have deleted grub for now. So I don't think it will interfere.

Can you elaborate a little bit on that one? How does it Break Windows 7?

I mean: I have to have both Windows and Linux. Is there any way of preventing corruption of Win7's bootloader (what gets corrupted is the boot loader, not Windoiws 7 itself, right?)

This has raised another worry in my head: perhaps I have to go back to WinXP?
My System SpecsSystem Spec

04 Dec 2010   #4


Not sure as I am not a Linux man - just that we see it here all the time.

Do you still have the formatted 100mb partition? Is it empty now? Did Win7 mark itself System Active?

Follow the steps above to move Active flag to 100mb and run Startup Repair repeatedly to move boot-critical files to it.

If you need to shrink Win7 to create 100mb Primary NTFS partition use free Partition Wizard CD which will also mark it Active for you.
My System SpecsSystem Spec
04 Dec 2010   #5

Windows 7 Ultimate 32 bit

I have formatted everything but Linux.

I reinstalled Windows 7 in its corresponding partition. It seems to me that the 100MB partition is now NTFS as I can see it from My PC and it has nothing.

I am currently creating the rescue CD from a friend's computer. Does it matter that it's another computer?

Update: so far I've done alsmost everything you told me. So far it seems to be working, I guess, but I have a problem: what are the three system repairs you talk about? I got a menu with several options, which three do I need?

Edit: Ah, wait, you said three startup repairs, not system repairs. I realize now I have to click on the first option three times. Silly me...
My System SpecsSystem Spec
04 Dec 2010   #6

Windows 7 Ultimate 32 bit
Am I doing it right?

Hi again.

I did what you told me. I now have several questions:

* How do I know I did it right?
I run the startup recovery until it started telling me that no problems were
Check this: Prior to this horrible incident, I had set up GRUB to contact the Windows bootloader in the 100MB partition and then fire it up. After
formatting the partitions (C: and the 100MB partition) I noticed that grub
could no longer start Win7. After doing all this, I notice that it can start it
again. Does it mean that I got it right? How do I tell that the 100mb partition
has been restored?
I read that it has some backup utilities there, how do I run these to check
they are there?

* Should I mark the 100MB partition as inactive again or should it stay like that?

* Finally I have a weird problem: At first (at the very beginning, long ago, before installing Linux) the 100MB partition had no drive letter and was invisible in Windows. I want it to be like that again should I remove the letter? What do I do to hide it? I'd like to remove the letter too.
My System SpecsSystem Spec
04 Dec 2010   #7


Please post back a screenshot of your full Disk Mgmt drive map with listings, using SNipping tool in Start menu. We can tell you if it is correct.

If 100mb is marked System Active, then you recovered it. You should now have your boot files on that partition, and the Repair console conveniently placed on the F8 Advanced Boot Tools menu.

What makes you think it is GRUB which is booting Win7 now? It should be System Reserved partition which is booting Win7. Is GRUB booting Linux now?

Do not ever move the Active flag without having a clear reason to do so, as your computer will become unbootable.
My System SpecsSystem Spec
04 Dec 2010   #8

Windows 7 Ultimate 32 bit

Here it is. Please tell me... I'm anxious

Both Windows and Linux are booting now.

I think GRUB is booting Windows because I reactivated it and had it boot Windows without telling it to look for the boot files inside C. Before, when I deleted the 100MB partition, it could not boot Windows from there. Now it can again, which leads me to think this is restored, but you tell me.

Oh, and please show tell me how to remove the letter and make it invisible in MyPC so that nobody can touch it.

Attached Thumbnails
My System SpecsSystem Spec
04 Dec 2010   #9

Windows 7 64bit

Hi mate,

Do you still have the windows disk that you installed from? if you do there is no real need to install the 100mb partition as you can always use it to repair any issues you have. Anyway what i would do is at the installation screen go to the command prompt and use diskpart to create an active partition of say around 80gb for windows. Leave the rest of the space as unallocated for now. Once that has been done install windows to this partition, you will see the 100mb partition is no longer there. I understand you want it but just wanna tell you how much easier i have found things by doing this.

Once windows has been installed to the partition i would normally install basic little things like graphics drivers etc i would not connect to the internet yet though as your get updates galore . Then create a disk image of the windows partition so if you now run into any problems you have a nice fresh image you can easily recover. I would then use disk management to create your other partitions however many you require, of course you would only be able to use a max of 3 more.

Thats just the way i like to go about a fresh install, i like to have 4 partitions so that 100mb one that windows creates only leaves me with 3 . Windows will install its MBR file to you windows partiton instead of the 100mb one its just personnal prefrence but i like to keep every together. Once you have created all the partitions you would like and installed all your applications games music etc i would then create another image of all the partitons so you now have the choice to recover to a nice fresh install or afresh install with all your applictions etc installed with all the most up to date updates.

There are some fab windows guru's on these forums who will put me right im sure if i have missed something, but like i said this is just the way i like to do things, everyone is different.

Hope this might have helped
My System SpecsSystem Spec
04 Dec 2010   #10
Bare Foot Kid
Microsoft MVP

W 7 64-bit Ultimate

Hello M R, welcome to Seven Forums!

It is not possible as Windows will not allow the drive letter of a drive that is marked as "System" to be changed or removed; I only read English but it seems the 100MB "System Reserved" partition is the "System" partition now and should work as intended for Windows 7.

Here are other options at these links below.

System Reserved : Create Using Disk Management

System Reserved : Create for Dual Boot
My System SpecsSystem Spec

 How do I re-create the 100mb partition?

Thread Tools

Similar help and support threads
Thread Forum
Acer Recovery DVD Won't Create 100MB System Reserved Partition
Greetings, When I first purchased my Acer AspireOne D255 back in 2010, I immediately deleted Windows 7 Starter and installed a dual-boot of XP Home and Ubuntu. However, recently I decided that I want Windows 7 back on the Netbook, so I ordered Recovery DVDs from Acer. I would like to set up...
Installation & Setup
100mb partition on disk
I just did a clean install of W7, again. I have the 100mb partition on the disk. I read somewhere that the data in this partition can be merged with the main system disk and then the partition recovered. At the present time the assignment of drive letters are incremented by one keeping me confused....
Installation & Setup
Way to get rid of the 100MB partition
I'm sure some of you know that particular versions of Windows 7 creates 100MB partition upon the its installation mainly for the BitLocker feature. I bought Windows 7 Ultimate from Amazon and it is one of them. I know it also contains WinRE, but I know Windows 7 can use its own partition where...
Installation & Setup
I NEED 100MB partition
Hello, Here is my situation: I have an older hard drive, which was used for my previous operating system. Disk has two partitions: System (C: ) and Data (D: ) I want to delete all data on System partition but nothing on Data partition. I also want to have only one system for booting at this...
Installation & Setup
Help reinstalling 7 without 100MB partition and more...
Hi, I currently have Windows 7 x64 Home Premium installed, and i'm going to reinstall it. At the moment, my drive is 500Gb and setup as follows: Now when I reinstall, I'd like to a) get rid of that 100mb partition and b) have a seperate...
Installation & Setup
Installation: Partition - why a 100MB system partition
Hello, I have started the installation process of windows 7 on a clean 1 TB hard drive. In order to ensure expediency of the read time of my primary drive, I choose the custom installation. When I did I partioned the drive as 250GB & 700GB. Hoever it also created a 100MB system partition on its...
Installation & Setup

Our Sites

Site Links

About Us

Find Us

Windows 7 Forums is an independent web site and has not been authorized, sponsored, or otherwise approved by Microsoft Corporation. "Windows 7" and related materials are trademarks of Microsoft Corp.

Designer Media Ltd

All times are GMT -5. The time now is 20:39.

Twitter Facebook Google+

Windows 7 Forums

Seven Forums Android App Seven Forums IOS App