[SOLVED] How do I partition a 8 Gb disk safely?

Nov 24, 2020
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I have an 8 Tb disk in my Windows 10 machine. The OS is safely installed on the C: drive. I want to partition the 8 Tb disk into 3 partitions of 1, 3.5 and 2.5 TB. I downloaded a program to do this. When I tried to click on 'convert to GPT' on the 8 Tb disk it said I have my OS on a separate disk and I might not be able to boot my machine. So, what can I do to partition my 8 Tb disk like I want?

I'm using the Demo edition of AOMEI Partition Assistant. Do I just delete the partition on the 8 Tb dive that says 'System reserved'?
 
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USAFRet

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Brand new install, just started this morning. And virtually no software installed.
Perfect.

Start over.

New OS install on the 500GB drive, with ONLY the 500GB connected.

What happens is, Windows puts the boot partition on whatever other drive is connected. Nothing you chose or did...Windows does that on its own.
Making further manipulation of that second drive uch more complicated.

So, a new install on the 500GB (see below)
Then, you can delete ALL partition on the 8TB, and reformat it as GPT. Giving you access to the whole 8TB space.

 

USAFRet

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Mar 16, 2013
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I have an 8 Tb disk in my Windows 10 machine. The OS is safely installed on the C: drive. I want to partition the 8 Tb disk into 3 partitions of 1, 3.5 and 2.5 TB. I downloaded a program to do this. When I tried to click on 'convert to GPT' on the 8 Tb disk it said I have my OS on a separate disk and I might not be able to boot my machine. So, what can I do to partition my 8 Tb disk like I want?
Firstly...why the partitioning?

Please show us a screencap of the current Disk Management window.
 
. When I tried to click on 'convert to GPT' on the 8 Tb disk it said I have my OS on a separate disk and I might not be able to boot my machine.
This is a standard response when creating new partitions on a new disk, because a new disk might change which the first disk in the boot order is.
If you actually have your OS on a different disk and not on this 8Tb disk you can safely go ahead and partition your heart out on that 8Tb, as long as you know how to enter your bios and change the boot drive there you will always be able to boot into your windows.

Don't use demo programs for something that windows disk manager can do.
 
Nov 24, 2020
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This is a standard response when creating new partitions on a new disk, because a new disk might change which the first disk in the boot order is.
If you actually have your OS on a different disk and not on this 8Tb disk you can safely go ahead and partition your heart out on that 8Tb, as long as you know how to enter your bios and change the boot drive there you will always be able to boot into your windows.

Don't use demo programs for something that windows disk manager can do.
Thank you for taking your time to answer my question.

When I try to use Disk Management to partition the disk, it will not let me make a partition bigger than 2 Tb. I tried right clicking on the drive and Convert to GPT disk is greyed out. I've read on this site that I need to convert the disk to a GPT disk in order to create larger partition. So, how can I convert the disk to GPT?

FYI - I have the OS on a 500 Gb SSD. I want to create 3 partitions in order to mimic my current disks on my old computer.
 
Thank you for taking your time to answer my question.

When I try to use Disk Management to partition the disk, it will not let me make a partition bigger than 2 Tb. I tried right clicking on the drive and Convert to GPT disk is greyed out. I've read on this site that I need to convert the disk to a GPT disk in order to create larger partition. So, how can I convert the disk to GPT?

FYI - I have the OS on a 500 Gb SSD. I want to create 3 partitions in order to mimic my current disks on my old computer.
Go to your motherboard website and look for a tool that unlocks drives above 3Tb.
 
Nov 24, 2020
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MBR2GPT, from Microsoft.
https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt

A drive formatted as MBR can only be 2.2TB.
Change it to GPT.
Thank you for responding to my question.

The disk I want to partition has a partition of 50 MB NTFS and is labeled 'System Reserved' I cannot delete this partition using Disk Management. Do I have to delete this partition before proceeding to convert the disk to GPT? If so, how do I delete this 50 Mb partition?
 

USAFRet

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Mar 16, 2013
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Thank you for responding to my question.

The disk I want to partition has a partition of 50 MB NTFS and is labeled 'System Reserved' I cannot delete this partition using Disk Management. Do I have to delete this partition before proceeding to convert the disk to GPT? If so, how do I delete this 50 Mb partition?
As requested, a screencap of your Disk Management window.

The OS is on a different drive?
And you had that drive AND this 8TB connected when you installed Windows?
 
Nov 24, 2020
63
2
35
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As requested, a screencap of your Disk Management window.

The OS is on a different drive?
And you had that drive AND this 8TB connected when you installed Windows?
Thank you for taking the time to address my question.

I just found out how easy it is to do screen caps on Windows 10. But I still don't see how to upload an image except from a URL. How do I upload my PNG file?

As I said the OS is on C: and is Disk 1. Drive 0 is the 8 TB disk. There is a 50 MB NTFS partition on Drive 0. I cannot delete this partition. Both drives were attached when I just installed Win 10.
 

USAFRet

Titan
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Mar 16, 2013
137,235
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Brand new install, just started this morning. And virtually no software installed.
Perfect.

Start over.

New OS install on the 500GB drive, with ONLY the 500GB connected.

What happens is, Windows puts the boot partition on whatever other drive is connected. Nothing you chose or did...Windows does that on its own.
Making further manipulation of that second drive uch more complicated.

So, a new install on the 500GB (see below)
Then, you can delete ALL partition on the 8TB, and reformat it as GPT. Giving you access to the whole 8TB space.

 
Nov 24, 2020
63
2
35
0
Perfect.

Start over.

New OS install on the 500GB drive, with ONLY the 500GB connected.

What happens is, Windows puts the boot partition on whatever other drive is connected. Nothing you chose or did...Windows does that on its own.
Making further manipulation of that second drive uch more complicated.

So, a new install on the 500GB (see below)
Then, you can delete ALL partition on the 8TB, and reformat it as GPT. Giving you access to the whole 8TB space.

Oh f..... I just did the build yesterday.

How do I prepare the computer to do a fresh install?
 
Nov 24, 2020
63
2
35
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Nothing special.

You have a Win 10 USB to install from?

Disconnect the 8TB, and do a full reinstall on the 500GB.

Follow the instructions in that link I posted.
Hi,

I was reviewing your earlier solutions. You mentioned using the MBR2GPT utility. Will that work on my 8 Tb disk? That would be a lot easier than disconnecting and reconnecting the disk in question.
 

USAFRet

Titan
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Mar 16, 2013
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Hi,

I was reviewing your earlier solutions. You mentioned using the MBR2GPT utility. Will that work on my 8 Tb disk? That would be a lot easier than disconnecting and reconnecting the disk in question.
You still have the issue of the boot partition living on the 8TB and not the actual C drive.

Personally, I would redo this install, as outlined above.
 
Hi,

I was reviewing your earlier solutions. You mentioned using the MBR2GPT utility. Will that work on my 8 Tb disk? That would be a lot easier than disconnecting and reconnecting the disk in question.
Just disconnecting and reconnecting wont help you either, the 8Tb disk shows up as disk 0 which means the systems starts from that, even if you disconnect it to reinstall windows as soon as you reconnect it it will again be disk 0 and the system will again start from there.

You should connect your windows drive to the sata cable the 8Tb drive is on, disconnect the 8Tb drive and then first try with windows repair to give the windows drive all the proper boot files and if that doesn't work re install windows.

As I already said way above if you can enter your bios you can just tell your system that you want it to boot from the windows drive in which case you wont need to do any repair or re installing or disconnecting.
 
Brand new install, just started this morning. And virtually no software installed.
You can also do it without reinstall. But this requires creating bootloader on 500GB drive manually.

To create bootloader on 500GB drive, execute from elevated command prompt. Regular command prompt will give error on last step.
(if you get any errors, then stop immediately)
diskpart
list disk
select disk 1
list partition
select partition 2
(select 505MB partition)​
delete partition override
create partition primary size=500
format fs=ntfs quick
active
assign letter=H
exit
bcdboot c:\windows /s H:

After that shutdown and try to boot with only 500GB drive connected.
If all goes well, then reconnect 8TB drive, clean it, convert to GPT, partition and format it.

 
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