Member Avatar for neilo19

Hello ,
I did something stupid and made a partitiion active and now it wont reboot (it says bootmgr missing) - Is there a way i can revert the partition back to its original state .

Thanks
neil

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A wrong "active" flag usually just breaks the boot chain by pointing the BIOS/MBR at a partition that does not contain the Windows boot files (bootmgr and the BCD on Vista/7). That is what causes the "bootmgr missing" message. resolved it by restoring the correct active partition on another PC, which is a perfectly valid recovery. There are other recovery options that avoid removing the drive and will work from the Windows Recovery Environment.

If the system is Vista/7, boot from the Windows installation DVD/USB, choose Repair -> Command Prompt and use DiskPart to pick the disk and set the correct partition active, then repair the boot code and BCD. A common sequence is:

diskpart
list disk
select disk 0
list partition
select partition X
active
exit

bootrec /fixmbr
bootrec /fixboot
bootrec /rebuildbcd

chkdsk C: /f

Be careful to select the right disk and partition. If the machine is XP, use the Recovery Console commands fixmbr and fixboot instead; for UEFI/GPT systems the process differs (EFI partition and bcdboot tools). If Bootrec reports no Windows installations, double-check which partition actually contains \Windows or \bootmgr — sometimes boot files live on a small "System Reserved" partition.

Other tips: verify BIOS/boot order and disconnect extra disks while repairing so Windows writes the MBR/BCD to the intended disk; check that the target partition is a primary partition (not a logical drive); and avoid repeatedly toggling the active flag without confirming which partition holds the boot files. and were pointing toward safe-mode and bootable partition tools — both can help, but use DiskPart/Bootrec from recovery for the most direct repair.

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Member Avatar for sittas87

you can go into safe mode and undo your actions.

Member Avatar for neilo19

Thanks - How can I do that if The screen freezes at boot up - (I can get to set up ) .I also tried booting via XP disk but it kept freezing.
It is a dell XPS720 if that helps

Member Avatar for sittas87

start pc press f8 a continuelly untill you get a boot up screen that gives you the safe mode option.enter for safe mode.
if it freezes before that slave your disk in another machine and run a chkdsk.now try to startup again.
ill stick with ya on this one
??

Member Avatar for acejames1

also try a boot disk of partition magic that way you can boot upto partition magic and change the drive parameters to how you want it using dos.

that might do the trick that sittas87 is thinking of as well if safe mode doesnt work

Member Avatar for neilo19

Thanks for your help I really appreciate it - Firstly I cannot get it to "safe mode"
I am now going to try another boot disk and see what i can get to from there.

Member Avatar for neilo19

I am back up and running - I took the disk out placed it into a USB external drive from another PC then in computer management restored the original partition as active and that worked .Thanks again for your help guys it was great to know I had support

Member Avatar for sittas87

no prob man glad you up and running
Cheers

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