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Windows 7: Active partition and boot problem

11 Dec 2009   #1

windows 7
Active partition and boot problem

Hi all,
I had a dual boot setup with windows 7 x86 and ubuntu 9.10, then I formatted the windows partition and installed x64 on it, as expected, it overrode grub thus i did not have any bootloader in the boot, then i reinstalled grub and got my ubuntu back but now i have the dreaded BOOTMGR issue in windows 7 boot, when i boot with windows 7 install disk, it detects the windows installation but the volume letter has now changed to E:. I suspect that the partition is not active anymore so that it is named E: and it cannot be booted from. How do i make the partition active again without reinstalling windows 7 and harming ubuntu? I presume windows 7 does not have any utility equivalent of fdisk.exe. any help will be greatly appreciated.

My System SpecsSystem Spec

11 Dec 2009   #2
Microsoft MVP


Try a Repair Install to allow Windows 7 to reconfigure the dual boot correctly, as it does when it is installed last.

There might still be a conflict with the GRUB so you might want to remove it now, or see if it is overwritten.
My System SpecsSystem Spec
11 Dec 2009   #3

windows 7

first of all, thanks for your fast response, but unfortunately i cannot boot to windows right now. it gives the bootmgr error. so i cannot do a repair installation.
My System SpecsSystem Spec

11 Dec 2009   #4
Microsoft MVP


Sorry, got ahead of myself.

Try booting into the Windows 7 DVD Repair console and run Startup Repair repeatedly until it starts up.

If this does not start it then try marking Windows 7 active first by booting into the Windows 7 DVD Repair Console>Recovery Tools to open a Command Line, then type:

SELECT DISK # (for Windows 7 disk)
select partition # (for Windows 7 partition)

Try rebooting and if necessary boot back into Windows 7 DVD to run Startup Repair repeatedly until Windows 7 starts up.

If this fails try again running the Diskpart commands but this time set the Ubuntu partition "inactive." Now try running Startup Repair repeatedly to repair/rewrite the MBR in Windows 7.

It is doubtful that Startup Repair will reconfigure the Dual Boot, so if not you may need to run the Repair Install.

Again, the GRUB bootloader is a problem here and often requires a full format to overcome in these situations.
My System SpecsSystem Spec
11 Dec 2009   #5

windows 7

hey, i've followed the tutorial to reset my mbr and it worked, i mean grub is gone, therefore i cannot boot to
ubuntu; but at least i have windows now in perfect shape with the correct volume letters. i am considering to redo the grub reinstallation, it might work this time

The weird thing is; now looking at the disk manager, i see that my swap and ext4 partitions have now become primary partitions, they were inside an extended partition before (while in the x86 configuration), i do not know how this has happened (whether ubuntu install or grub reinstall or fixmbr caused it), would it mean that even if i get the grub back, ubuntu may not be working fine as it was inside an extended partition before? Sorry the situation is too complicated to write clearly i apologize for that
My System SpecsSystem Spec
12 Dec 2009   #7

windows 7

hey, i tried re-installing grub then again i received the bootmgr error, then used diskpart to make windows 7 partition active then rebooted and ran startup manager again (this time windows was detected in c: partition), and voila... i have grub as the bootloader and both ubuntu and windows 7 up and running. thanks for the tip. i think the problem is caused by the grub reinstall which somehow sets the 100mb partition as active (i've checked), once the active is restored to windows partition, everything seemed to work fine.

Actually i am surprized that runnning startup manager did not overwrite the grub (luckily). I think it is because grub is located in the very first sectors of the harddisk whereas windows boot files are in c: so that startup repair only configured c: partition, keeping grub intact. Does it make sense? Thanks.
My System SpecsSystem Spec
12 Dec 2009   #8
Microsoft MVP


Yes, I've found that on most dual boots, Windows 7 DVD Startup Repair seems to limit its repairs to the Windows 7 installation, even rewriting the MBR to the Windows 7 partition when it was previously on the XP or Vista one.

In order to get Windows 7 to then correctly reconfigure the boot, it requires running a Repair Install from the desktop, which simulates Windows 7 again being the last-installed OS.

However, GRUB is a wild card and very hard to understand in relation to Windows 7 dualbooting, so you are fortunate to have sorted it out so well.
My System SpecsSystem Spec

 Active partition and boot problem

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