Windows 10: Windows 10 reformatted my NTFS drive to be a GPT drive

This is a very weird problem. So I am just going to present what happened and see if anyone has ever heard of this.


I was using Windows XP. I have a Dell laptop and I am using XPx86 version. My laptop has 8GB of memory - only 4GB are being used. I had no idea, when I bought the system years ago, that it really was a 64-bit system. So I installed the 32-bit version. This system is rock solid but I'm going to lead in with this information.


I recently decided to put together a desktop system. So I got a Gigabyte motherboard, 64GB of main memory, a 2TB magnetic hard drive (an HDD I believe they are now called), and an Nvidia graphics card. Setting my XP laptop to one side, I began installing my software. Everything went well and the system is up and running.


Now we get into the weird stuff.


I have four 2TB Seagate external hard drives. These are, more or less ok still. But then I have two 8TB hard drives. This is where the problems occur.


Both 8TB disk drives I got when I only had my XP laptop. The disk drives were GPT. But I wanted to use them on my XP laptop. So I hooked up the first drive and, using Disk Manager, I deleted all partitions and then made three NTFS partitions. Each partition was set to 2.39GB. The left over space I just left alone. I formatted the partitions and then backed up my music and some other items to the drive. Then I did the same for the second drive and put copies of my software on the disk drive. So far - everything is cool. No problems.


The problems started when I put the first of these 8TB disk drives onto the Windows 10 system. (Remember these are external USB Seagate disk drives. So just plug and play.) At any rate, the drives first worked without problems. Then I unmounted the drive, put it back on the XP system, copied a few files onto it, dismounted the drive, put it back on the Windows 10 system, did more stuff and so on for about six or seven times. Then, when I went to plug the disk drive back into the XP Laptop - it was blank.


Yes. That is right. It was blank. I could not even mount it. So I unplugged it, went back to the Windows 10 box, plugged it back in and - it was blank.


I went back and forth several times but the disk drive was blank. So I did my next dumb thing - I tried the second 8TB disk drive. It worked for about four times of back and forth and then it too suddenly became blank.


So I did a lot of tests, downloaded and tried seven or eight programs and even downloaded C++ source code to read and write to USB drives. None of the programs worked all that well except one - usbtreeview. This program would show me all of the information about each and every usb device on my XP laptop. This was when I found out that the drive had been reset to being a GPT disk drive.


So back to the Windows 10 system I went and I finally got the drive to show up again. Sure enough - main partition was now GPT with three NTFS partitions farther along on the disk drive.


Since then I have backed everything off of the hard drive to other hard drives, I then wiped the NTFS partitions, deleted them, cleared the entire hard drive of any kind of partition software. Then I created a single GPT partition (ie 8TB) and am now restoring all of the software to the hard drive.


So now you have all of that information.


My question is - has anyone else had this problem happen to them? Has Wndows 10 ever automatically ever changed an NTFS disk drive over to GPT before?

:)

 

Windows 10 boot drive

Also?
You mean you had issues with large drives and previous Operating Systems?
NTFS up to 2.2Tb
GPT over a Pb.
If you want to use NTFS partition the drive.

 

Windows 10 Installation Issue "Can't install Windows on GPT drive"

There are people who are trying to install Windows 10 (Clean Installation) on either a new HDD/SDD OR an old HDD/SDD. But when you selected a drive and click Next, you received an error "Can't install Windows on GPT drive".

When installing Windows on UEFI-based PCs using Windows Setup, your hard drive partition style must be set up to support either UEFI mode or legacy BIOS-compatibility mode.

For example, if you receive the error message: “Windows cannot be installed to this disk. The selected disk is not of the GPT partition style”, it’s because your PC is booted in UEFI mode, but your hard drive is not configured for UEFI mode. You’ve got a
few options:

• Reboot the PC in legacy BIOS-compatibility mode. This option lets you keep the existing partition style. For more info, see
  
  Boot to UEFI Mode or Legacy BIOS mode.
• Reformat the drive for UEFI by using the GPT partition style. This option lets you use the PC’s UEFI firmware features.
  
  You can do this yourself by reformatting the drive using the instructions below, or if you need to preserve the data, use a third-party utility to convert the drive to GPT format.

(source:https://technet.microsoft.com/en-us/library/Dn336946.aspx)

In addition, here are steps to convert your HDD to MBR or GPT.

*Note: Make sure that you have a back of all your files.

1. Boot from the installation device (USB or DVD).

2. Once you reach the "Install" page. Immediately press and hold SHIFT KEY + F10 KEY.
This will open command prompt (The black box DOS program).

3. Once the Command Prompt is open, proceed to type the following command line.

Method 1:Short Method

a. Type diskpart and then hit enter. This will enable command prompt to enter disk partitioning mode.

b. Now type list disk and then hit enter. You will then see a list of disk drives.

c. Please make sure that you know the current size of your HDD. Select it by typing
select disk 0 . Replace 0 with the right drive number.

d. Now type clean to unallocated it.

e. Now type create part pri and hit enter to create primary partition.

f. Next is to type select part 1 and then hit enter.

g. Now type format fs=ntfs quick and then hit enter. Take note this will reformat the whole hard drive. So make sure you have a backup of everything.

h. Now type select disk 0 again and then hit enter.

I. Now please type detail disk and then hit enter.

j. You will see a volume number, type select volume 1.

k. Now please type delete volume.

l. Now type convert mbr if you need gpt then type convert gpt and then hit enter.

m. Now please go so step c up to step g then type exit.

And now just restart your pc and you will be able to install Windows 10 Now.

 

Reformatting the c drive

Hi,

To better assist you with your concern, we would like to know the following:

• What the exact error message that you're getting when you try to reformat your C: drive?
• Why do you want to reformat your your C: drive?
• What troubleshooting steps have you taken to resolve the issue?
• Did you make any significant changes to your computer prior to the issue?

We look forward to your reply.