How do I convert to GPT?

[lexidobe]

Hello everyone, I am currently using Windows 7 and I am trying to dual boot Windows 10 LTSC on a second partition. However, when I try to install Windows 10 on my second partition, it says I can't install WIndows on the partition because it isn't GPT. So I am wondering how I convert that partition to GPT so I can install Windows 10 on it without losing my data or corrupting Windows 7.

 

I already tried 2 different partition managers and neither worked, and I also tried Diskpart in Windows 7. I didn't try diskpart in the WIndows 10 installer because I wasn't sure if it would wipe my drive since I couldn't select just partition 2 and it instead selects the whole drive. So how do I fix this? Thank you in advance!

[Windows7ge]

When converting a disk to GPT it has to be done before any partitions are installed on it otherwise it'll remain MBR. If the disk is already MBR with a Windows install and you want to install another instance next to that on another partition you have to use a MBR installer. You cannot convert to GPT without wiping out the first install.

[lexidobe]

27 minutes ago, Windows7ge said:

When converting a disk to GPT it has to be done before any partitions are installed on it otherwise it'll remain MBR. If the disk is already MBR with a Windows install and you want to install another instance next to that on another partition you have to use a MBR installer. You cannot convert to GPT without wiping out the first install.

Thanks. What's weird is that I did this before. 1 month ago I did the same thing on the same system. I got an error the first time, but I restarted the system and it installed perfectly fine. Is it just being a pain in the ass because this is the LTSC version?

[Windows7ge]

1 minute ago, lexidobe said:

Thanks. What's weird is that I did this before. 1 month ago I did the same thing on the same system. I got an error the first time, but I restarted the system and it installed perfectly fine. Is it just being a pain in the ass because this is the LTSC version?

No, this has to do with how the installer is set up. By default creating a bootable media using something like the Windows Media Creation tool will automatically tell the installer to use the GPT partition scheme because it's the newer standard. For backwards compatibility you'd want to use something like Rufus and tell it to use Legacy BIOS not UEFI which should make the installer use MBR. This would allow it to work on a MBR disk.

[lexidobe]

1 minute ago, Windows7ge said:

No, this has to do with how the installer is set up. By default creating a bootable media using something like the Windows Media Creation tool will automatically tell the installer to use the GPT partition scheme because it's the newer standard. For backwards compatibility you'd want to use something like Rufus and tell it to use Legacy BIOS not UEFI which should make the installer use MBR. This would allow it to work on a MBR disk.

Thank you so much for your help. I used Rufus both times, but I didn't change any of the default settings either time. I changed from GPT to MBR this time, so maybe it will work. I will report back once it finishes creating the bootable USB drive and I try it.

[lexidobe]

27 minutes ago, Windows7ge said:

No, this has to do with how the installer is set up. By default creating a bootable media using something like the Windows Media Creation tool will automatically tell the installer to use the GPT partition scheme because it's the newer standard. For backwards compatibility you'd want to use something like Rufus and tell it to use Legacy BIOS not UEFI which should make the installer use MBR. This would allow it to work on a MBR disk.

Nope, same problem. I am going to try installing from Windows. EDIT: I can't because it won't let me select the partition I want to install it to. 

Edited August 11, 2019 by lexidobe

[Windows7ge]

Just now, lexidobe said:

Nope, same problem. I am going to try installing from Windows 

It's possible that Windows itself want to use GPT. This "trick" use to work on Windows 7.

 

Are you not able to use a second physical HDD/SSD? Dual boot will behave identically and you get the added perk of if one drive dies you have the other as a backup/recovery.

[lexidobe]

Just now, Windows7ge said:

It's possible that Windows itself want to use GPT. This "trick" use to work on Windows 7.

 

Are you not able to use a second physical HDD/SSD? Dual boot will behave identically and you get the added perk of if one drive dies you have the other as a backup/recovery.

Windows 10 is just a total pain in the ass. Worked once, but now it won't work again for no reason. Unless it's something specific to the LTSC version, I don't understand how I ever got this to work in the first place. But since I got it to work once, I'm sure I can do it again.

 

I could install it on an extra drive, but I would prefer to install it on my Samsung 960 Pro because it's a lot faster than any of my extra sata drives and I want to have as much of a direct performance comparison as possible.

 

I am going to see if there is a setting in the UEFI to use legacy boot mode or something similar, maybe that will work.

[Windows7ge]

3 minutes ago, lexidobe said:

I am going to see if there is a setting in the UEFI to use legacy boot mode or something similar, maybe that will work.

Bringing back a vague memory. I believe there is a BIOS option to Enable | Disable Legacy boot (probably disabled of your board supports UEFI). Definitely check for that.

 

But then again you're running Windows 7 on an MBR disk under (presumably) UEFI so Legacy boot might do nothing. Well, you don't have anything to lose besides time. If that's not very important right now .

 

8 minutes ago, lexidobe said:

I could install it on an extra drive, but I would prefer to install it on my Samsung 960 Pro because it's a lot faster than any of my extra sata drives and I want to have as much of a direct performance comparison as possible.

Depending on your workload going from SATA SSD to NVMe SSD there isn't a huge leap. Unless you have large project files you won't really see the difference. If you're trying to a direct performance comparison between the two OS's I can see why you want this but unless you can convince Win10 to install on MBR then you'll need to step Wind7 up to GPT.

 

If anything you might want to do the latter. A fresh install of each fully updated would yield the most accurate results.

[lexidobe]

3 hours ago, Windows7ge said:

Bringing back a vague memory. I believe there is a BIOS option to Enable | Disable Legacy boot (probably disabled of your board supports UEFI). Definitely check for that.

 

But then again you're running Windows 7 on an MBR disk under (presumably) UEFI so Legacy boot might do nothing. Well, you don't have anything to lose besides time. If that's not very important right now .

 

Depending on your workload going from SATA SSD to NVMe SSD there isn't a huge leap. Unless you have large project files you won't really see the difference. If you're trying to a direct performance comparison between the two OS's I can see why you want this but unless you can convince Win10 to install on MBR then you'll need to step Wind7 up to GPT.

 

If anything you might want to do the latter. A fresh install of each fully updated would yield the most accurate results.

Thank you for your help. I set the boot option to legacy and I was able to install Windows 10 no problem.

 

Oh and by the way Windows 10 LTSC is awesome! There is no bloatware and it runs very fast! I would say that the speed is slightly better than standard 10 "out of the box", and better than standard Windows 10 has ever run after disabling unused services.

 

Too bad Microsoft didn't make the regular versions of 10 the same way. If they did, people might actually like the OS.

[Windows7ge]

Good to hear. Glad you figured it out.

52 minutes ago, lexidobe said:

Too bad Microsoft didn't make the regular versions of 10 the same way. If they did, people might actually like the OS.

I'm annoyed that the Pro version is full of useless bloatware. You would think buying Pro that the intention is in an office deployment where you don't want useless Games, or home user demographic type applications but both are bundled in Pro. I find that pretty stupid. Bare metal versions aught to be more easily accessible to consumers outside of having to buy the Enterprise or an Embedded version.

 

There are 3rd party applications out there designed to uninstall a lot of the bloatware included in Windows but I've not tested any. Can't remember any names either at the moment.