Solved Preventing a Pre-OS environment from starting

October 22, 2012 at 12:30:12
Specs: Windows Server 2003
On a Windows 2003 server I needed to re-size (reduce) the data partition (D:) in order to increase the system partition (C:). I used AOMEI Partition Assistant Lite Edition 5.1, which is free. The program said it needed to do this in a Pre-OS environment, so I clicked OK to re-boot.

The server never came back to life, but stalled with a message which reads
the operation abort - information code 12
disk environment has changed - please reboot

Pressing any key had no effect, so I was forced to power off, but then the same thing happens.
I can't find a way to stop the AOMEI Pre-OS from starting.

I have emailed their support section twice in 24 hours, but have still had no reply, and I am getting desperate (and so are the users!).

I have managed to get into the recovery console from the Server 2003 CD, but I still don't know how to prevent the automatic startup in this Pre-OS mode.

I'd be very grateful for any ideas.

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October 22, 2012 at 13:08:52
You may try the following (ignore the required registration and scroll down the page)


Be aware that may be dangerous, but it may be your ultimate chance.

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October 22, 2012 at 14:11:32
You can't reduce the d: data partition and then expect to enlarge the c: partition.

Problem is though you shrunk the d: its shrinkage is at the end of the partition not at the beginning.

To expand c: it literally would have to "jump over" d: to get to the available space.

Proper procedure is to backup d: and then delete it. Expand c: then create a new d: and restore from backup.

At this point your disk is corrupt. A new install and a restore from backup is your only option now.

You could try going into recovery console and running the utilities fixboot and fixmbr but I suspect the damage is more extensive than the boot area of the disk.

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October 22, 2012 at 22:45:27
✔ Best Answer

This is not a common error of AOMEI Partition Assistant, the computer reboot to Pre-OS mode is decided by a file called "ampa.exe", it is located in "C:/Windows", so to solve this problem, you could create a winPE system and then boot from this system to locate this file and delete it or connect your system disk to another machine and then delete this file. And if you could enter the Advanced setting, when the computer reboot, you maybe warned that to press particular key to this time press F8 to enter advanced setting and then select back to the " "back to Last known healthy computer configuration". After the process completed you could come back to your last known healthy computer configuration.
Hope it could help.

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Related Solutions

October 23, 2012 at 01:14:20
#2 I believe you are wrong to say that "You can't reduce the d: data partition and then expect to enlarge the c: partition." Most partition-resizing programs allow you to do this by shrinking D:, moving it, then expanding C:. I've done it several times with various programs. But, in this case, something has gone wrong with the process. Partition resizing is always a potentially risky procedure.

@OP You should try the advice given in #3. If that doesn't work then cut your losses - reinstall the OS and restore from your backups; this is the quickest way to get your users back online. Personally, I would have done this as soon as it was apparent that there was a problem; finding the cause is nice, but getting the system running quickly is better.

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October 23, 2012 at 02:50:06
Thanks to everyone for the suggestions, especially jiong2521. I also got a reply from Aomei direct, delayed only because of the time difference. Following their advice, as I was already in the Recovery Console, I deleted the file ampa.exe in C:\Windows, and then exited the Console and rebooted.
I am happy (I can't tell you how happy) to say the server then booted normally, and all the data was intact. The data partition had not been re-sized, but that's a relatively minor issue now.
It would have taken a week just to re-install from scratch, as it's a fairly complex setup, so I'm very relieved that I don't have to do this.

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October 23, 2012 at 03:56:22
Just a suggestion relating to your original problem. You could always try moving some folder(s) to D: and linking them back to their original location(s) via a junction point. That way they will still appear to be on C: as far as the system is concerned.

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October 23, 2012 at 07:43:16
You should also make a clone of the system so you don't have to spend a week reinstalling. You clearly need to review your disaster recovery plan.

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