Booting from GPT disk

mubs

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My goal is to install W10 in a dual-boot config with my existing W7, migrate all apps to W10 over a period of time, have it stable, then discontinue W7.

My motherboard is an Asus P8Z77-V with UEFI Bios. I'm on the last released version of the BIOS (2013-09).

Many full moons ago I moved my W7 installation from the then 1GB HDD to an SSD using Minitool Partition Wizard. Then the 1GB died, and I replaced all my drives with 2 x HGST 3TB drives, both of which are in Basic GPT mode. All was well. When I installed the first 3TB, I left 200 GB in the front thinking I may need it in the future if the SSD dies or starts acting flaky.

I spent the better part of 5 hours now trying to move my W7 installation to that 200 GB first partition on the 3TB drive.

Move OS Wizard in Minitool Partition Wizard wants to copy the entire source HDD (SSD) to the destination drive, not just the OS partition. This means it will wipe out multiple partitions on the HGST and all the data on it. The Copy Partition appears to work, but when I select the newly copied partition, the option to set it active is grayed out. Another option that reads Set Windows Partition errors out saying the newly copied partition does not have a Windows folder. But browse that partition, and sure enough it has the Windows folder.

I tried using Terabytes Image for Dos, which has a copy option. This appeared to copy the partition, and I had selected an option to make the newly copied partition active, but when I pulled power out of the SSD and tried to boot, the system couldn't find a boot partition (BIOS was changed to look at the first HGST for boot).

One option is to leave W7 on the SSD, and install W10 on the 200 GB first partition of the GPT 3TB drive. Will it boot? I don't know. Anybody know?

Another option is to install W10 on the SSD as a second OS. W7 is using 46.5 GB and 153.5 GB is free (I have already reserved an additional 63 GB for defect mapping etc. in Samsung Magician sw).

Recommendations please? TIA!
 

ddrueding

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Installing OSes on drives with data scares me quite a bit. In fact, installing OSes on drives with an existing partition structure isn't something I've done in years. If there is space on the SSD that already has 7, I'd disconnect your data drives and install 10 alongside 7 if it lets you. Haven't tested that one, either.
 

mubs

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Dave, I've had OS and data on the same drives since forever. But, all non-OS stuff has lived in separate partitions, plus all data is backed up almost real-time to a second drive with no OS, so it's never been a problem.

I could shrink the current W7 partition on the SSD and make another for W10. ~70 GB total for W7 (currently using ~42 GB) and a little over 80 GB for W10 should be sufficient.

Interesting that there's been 23 views but only your comment. On Storage Forum, no less !

Is nobody booting from a GPT disk? I understand it's because everybody must be using an SSD for booting. Still I'd think people with NAS boxes etc. would face the situation I'm facing.
 

ddrueding

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Even my NAS boxes have SSDs for the OS ;)

Shrinking the W7 partition and putting both on the SSD seems to make the most sense. It will also give you an apples/apples comparison of the speed.
 

mubs

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I shrank the W7 partition, created a new primary next to it and installed W10 on the SSD. Now I'll never know how to make it boot from a GPT disk :(
 

Handruin

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I'm of the same view as ddrueding in that installing an OS on a drive with data is not something I bother with these days as I don't want to mess with losing the data. I only have experience with setting up GPT for my boot devices under CentOS Linux and then format using ext4 as the filesystem. The drives are 500GB and only a single OS is put on them. I also boot using UEFI. I haven't messed around with the Windows boot loader to have any insightful info in how you can get another OS to boot from a different drive.

FWIW, I also use an SSD to boot my NAS from.
 

mubs

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Thanks Handy. In the past I have booted multiple OSes from different drives; it's not so difficult. It's GPT that's the spanner in the works here. And if a partition is already created at the beginning of a drive for the OS to live in, having data in other partitions on the same drive is generally very low risk unless the OS being installed insists on using the whole drive. This seemed to be the case with the Move OS Wizard in Minitool Partition Wizard, so I didn't go through and backed out of that option.
 

Howell

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I have also not installed an os on an non-empty drive in years. It is my understanding from the halted research I was doing for my laptop that gpt goes along with uefi and uses a fat32 efi partition at the beginning of the drive for the boot process. It didn't need to be very big but it does need to be there. I'm not sure why those tools I've never heard of weren't working for you.
 

mubs

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Well, my motherboard does have UEFI, and there was a 128 MB reserved partition at the beginning of the disk (I think this was to make the partitions "aligned" - done by either W7 or Minitool Partition Wizard, can't remember) followed by 200 GB of free space. At this time it will have to remain an unsolved mystery!
 
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