Up until recently I've been happily running a (pre-built) Windows 7 Pro box with the following:

  • Gigabyte Z77-D3H motherboard (UEFI Dual BIOS, vF19b)
  • Crucial M4 SSD (120Gb boot drive)
  • Western Digital HDD (approx 1Tb data drive)
  • CD/DVD drive

All drives were connected up via separate SATA connectors (SSD on channel 0, HDD on channel 2, CD/DVD on channel 5). The problems started when I noticed the SSD was becoming a little too full for comfort (approx 6Gb free), so I purchased a replacement drive (OCZ-ARC100 240Gb).

Using Acronis TrueImage 2013, I temporarily replaced the HDD with the new SSD, and cloned the data across. So far, so good - until I attempted to reboot with the new SSD and HDD plugged back in. That's when I was left with:

BOOTMGR is missing

After much head-scratching, cursing and swapping of drives (and the help of a Windows repair CD), I've managed to get the SSD and Windows back up, but only with the new SSD plugged in. The moment I try to reconnect the HDD, I'm back to "BOOTMGR is missing".

I've enabled AHCI in the BIOS, and have the following boot options:

  • Windows boot manager
  • P0: OCZ-ARC100
  • CD / DVD drive

Hard drive BBS priorities:

  • P0: OCZ-ARC100
  • P2: WDC WD10EZRX-00A8LB0

CD/DVD ROM drive BBS priorities:

  • P5: TSSTcorp CDDVDW SH-224BB

Other potentially related settings:

  • CSM support: always
  • Boot mode selection: UEFI & legacy
  • PXE boot option control: disabled (other options: UEFI only / legacy only / legacy first / UEFI first)
  • Storage boot option control: legacy only (other options: UEFI only / legacy first / UEFI first)
  • Display boot option control: legacy only (other options: UEFI only / legacy first / UEFI first)

Note If "CSM support" is switched to "never", all sub options are hidden, but on reboot the BIOS never reappears, until the CMOS battery is temporarily disconnected!

Using a Partition Wizard boot CD, I've found the following info on the various drives:

Old Crucial SSD (MBR):

  • System reserved (106Mb, NTFS) – active & boot
  • Data (119.13Gb, NTFS)


  • GPT reserved (128Mb)
  • GPT EFI system partition (100Mb, FAT32) – active & boot
  • GPT data partition (223.35Gb, NTFS)


  • Storage (881.51Gb, NTFS)
  • Acronis SZ (50Gb, FAT32)

The only difference between my old and new SSD that I can see (other than the capacity) is that for some reason, the new one is using GUID partition tables (GPT) instead of MBR.

Partition Wizard offers the ability to convert GPT drives to MBR - can anyone confirm if this is likely to be the missing step which will convince my machine to read both drives?

Any assistance with this would be much appreciated!

If I learned nothing else, it's to back up BIOS settings before I unplug anything. Lesson learned!


2 Answers 2


It appears you cloned the data but not the proper boot area and the most reliable solution will be to prepare a new clone (sorry).
I recommend using Clonezilla which can handle both MBR and GPT partition formats.
You can store the clone on the HDD as backup (device-to-hdd) or use device-to-device like you did.
I just made an identical migration last week (although with Samsung SSDs).
If you do pick Clonezilla - make sure to review this and this and print a hard-copy. (step-by-step save & restore guide)

  • Finally got a chance to backup recent files and try the clone again (this time using Partition Wizard). Thankfully the MBR format was copied across, so adding the HDD back into the mix didn't cause issues.
    – Conan
    Commented Dec 28, 2015 at 22:26

It appears that your disk clone tool, for whatever reason, created a GPT (UEFI) installation out of your old MBR (Legacy) installation. As a result, Windows will not boot because it has been installed in Legacy (Non-UEFI) mode.

I recommend to try the cloning again, but before you do, set the BIOS option "Boot mode selection" to Legacy only.

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