GPT disk and Active partition

I had a 1TB hard disk installed in my PC with C: and D: partitions on it. The other day I added an SSD and used the bundled Acronis True Image software to migrate the Win7 64bit OS from the hard disk to the SSD. True Image forced me to use the GPT partition style for the SSD, said it must be for the SSD to be bootable. Not sure why as the hard disk is MBR format but I had no choice so I just went with it and it boots fine.

Anyway, I now want to delete the old C: partition on the HD to get the space back but it's marked as Active and I can't see any way (in the Disk Management tool anyway) to un-mark it as such. I also don't seem to be able to mark the new C: partition as Active either - is that something to do with the SSD being a GPT disk? Can I safely delete the old C: partition without breaking stuff?

Also, I ended up with a 100Mb "EFI System Partition" at the start of the SSD but it's not mounted to a drive letter etc. and I can't see a way to do that. Is there any way to view the contents of this and is there anything interesting in it if there is?

you could try just unplugging the old HDD and see if it boots?

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Originally Posted by 8bit

Anyway, I now want to delete the old C: partition on the HD to get the space back but it's marked as Active and I can't see any way (in the Disk Management tool anyway) to un-mark it as such. I also don't seem to be able to mark the new C: partition as Active either - is that something to do with the SSD being a GPT disk? Can I safely delete the old C: partition without breaking stuff?

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You'll probably want to use Diskpart. Or if you want something with a better GUI, just boot into a PartedMagic disk.

Also, I ended up with a 100Mb "EFI System Partition" at the start of the SSD but it's not mounted to a drive letter etc. and I can't see a way to do that. Is there any way to view the contents of this and is there anything interesting in it if there is?[/QUOTE]

The 100Mb at the start is the recovery tools. Leave them be :) Nothing you want to mess with.

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Originally Posted by jackvdbuk

you could try just unplugging the old HDD and see if it boots?

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I did that the very first boot after cloning the C: drive over and it worked fine. I guess I'm concerned that the Active partition is now the old partition, even though it's not mounted, so if I delete it then I may not have a bootable OS.

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Originally Posted by Agent

You'll probably want to use Diskpart. Or if you want something with a better GUI, just boot into a PartedMagic disk.

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OK, is the Disk Management snap-in no good for this then? What will I be able to do with Diskpart of PartedMagic that I can't with the MMC snap-in?

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Originally Posted by Agent

The 100Mb at the start is the recovery tools. Leave them be :) Nothing you want to mess with.

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But I like messing with stuff :) What recovery tools though? I didn't install any, the PC isn't an off-the-shelf one from Dell or such like, it's a home-build so not sure how anything got on there as it was True Image that created the partition. How do I access the recovery tools if I need them?

If the old C: drive is appearing as active in windows and the new one isn't....and it won't let you change them.....then it would say to me that the boot order in the bios is incorrect and you are booting from the active partition of the old C: drive, hence windows marks it as such and stops you doing anything to it.

I would do the F10/F11/F12 (whatever it is on your motherboard) to choose boot menu and select the SSD (or possibly Windows Boot Manager if you have EFI enabled) and see if you can get the active partition change in Windows before performing any "maintenance" on the original disk.

It's definitely booting off the new SSD, it's much, much faster than the old C: drive on the mechanical disk.

Just had a look in the BIOS (EFI) and the first boot device is already the Windows Boot Manager entry. Second is the BDROM drive and that's it, I disabled booting from any other devices.

The SATA ports seem to be enumerated oddly. Port 0 has the disk and Port 1 has the SSD. I have the disk in a 3Gbps SATA port and the SSD in one of the two 6Gbps ports so I wouldn't have thought they'd be number consecutively.

I haven't actually attempted to delete the old C: partition yet. If I try and it lets me do it then will it just mark the new C: as active at next and subsequent boots?

OK just to round off this thread, I took some backups the other night and binned the old C drive partition on the hard disk. Still boots fine off the SSD. I now have no "Active" partitions at all, I guess that's an MBR thing that isn't required/supported with GPT on a UEFI system.

Thanks to all who helped :)

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Originally Posted by 8bit

Also, I ended up with a 100Mb "EFI System Partition" at the start of the SSD but it's not mounted to a drive letter etc. and I can't see a way to do that. Is there any way to view the contents of this and is there anything interesting in it if there is?

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The EFI System Partition is where UEFI systems store pre-OS stuff. You can have EFI applications corresponding to multiple OSes (e.g. Windows and Linux), for utilities (like recovery tools, or memory tester), or generally any other junk you might want on the disk but outside the OS.

In your case, you're only interested in one file on there, bootx64.efi, which contains the Windows Boot Manager. This EFI application can boot Windows.

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Originally Posted by 8bit

Also, I ended up with a 100Mb "EFI System Partition" at the start of the SSD but it's not mounted to a drive letter etc. and I can't see a way to do that. Is there any way to view the contents of this and is there anything interesting in it if there is?

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In case anyone does want to see in the ESP volume, you can do the following

Start an elevated Cmd prompt

type 'mountvol x: /S'

now you can browse around drive X from the command prompt

If you want to use Explorer to be nosey, run explorer.exe as an elevated process, and it will show up there.

The ESP will remain mounted until you reboot, or unmount it ('mountvol x: /D' in case you needed to know).

Thanks for the info guys, interesting. I've just mounted that ESP volume, the contents of X:\EFI\Microsoft\Boot look very much like the contents of C:\Boot. I'm guessing that's not a coincidence?

So if I added another disk (I have a spare 64GB SSD lying around here) to install another OS on, say Linux, if I installed Linux onto that then would I get more stuff in this ESP volume or would I end up with another ESP volume on the other SSD?

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Originally Posted by 8bit

Thanks for the info guys, interesting. I've just mounted that ESP volume, the contents of X:\EFI\Microsoft\Boot look very much like the contents of C:\Boot. I'm guessing that's not a coincidence?

So if I added another disk (I have a spare 64GB SSD lying around here) to install another OS on, say Linux, if I installed Linux onto that then would I get more stuff in this ESP volume or would I end up with another ESP volume on the other SSD?

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The "correct" behaviour would be to put more stuff in your existing ESP

OK, so do I then have more options in the BIOS/UEFI, so alongside "Windows Boot Manager" will I find something like "Fedora Boot Manager", for example?

Try and will see.It is mostly down if you have enough free time to play around.

Free time? We just had our first baby about 4 months ago, so free time is in short supply :) This is the only PC in the house for the time being too so I don't want it out of action for any length of time either.