mbr gpt partition help

hello guys I need help, in windows 10 I converted the ssd disk with mbr partition to gpt using the mbr2gpt / convert command from cmd. Everything works perfect and windows works in uefi mode.
but it turns out that I want to install on another partition of another hard drive (HDD mbr ntfs) windows 7 and during installation it tells me that windows cannot be installed on the selected partition and before the conversion I could install it.
The first thing I thought is to convert the ssd to mbr again, with minitool partition wizard but in the attempt I get a sign saying that the disk contains system partitions and could be unbooteable.
also what I have set is that since I made the gpt convertion I get on the disk ssd 2 more partitions:
efi system partition
OEM partition (System Reserved)
I comment that I tried all the options from the bios and nothing worked for which I ask for your help to be able to also install the windows 7 on the other hard disk hdd as I did before,
having both operating systems. thanks all i hope your help...

Disconnect the SSD while installing Windows 7 to the HDD. In fact, it's always recommended, if you don't know exactly what you are doing, to disconnect other drives when installing Windows to the desired system drive.

Actually, though, we should probably see a screenshot of disk management first:
Disk Management - How to Post a Screenshot of

NavyLCDR said:

Disconnect the SSD while installing Windows 7 to the HDD. In fact, it's always recommended, if you don't know exactly what you are doing, to disconnect other drives when installing Windows to the desired system drive.

Actually, though, we should probably see a screenshot of disk management first:
Disk Management - How to Post a Screenshot of

This is what I would do:
Disconnect the SSD
Boot the computer from your Windows 7 DVD or USB flash drive
After you select the custom install option, on the next screen where it shows drives and partitions, delete the 200 GB partition that you are trying to install Windows 7 to.
That will leave you with a chunk of unallocated space on that drive. Click on the unallocated space to highlight it, then click next to start the install.

After you get the install of Windows 7 on the single HDD done and booting, then reconnect the SSD. You'll be left in a situation where you will have to select which drive to boot from using the UEFI (BIOS) boot menu, but we can easily set up a dual boot menu from there. Come back and post another screenshot of disk management from Windows 10 and we'll tell you how to set up a dual boot menu and clean up the extra partitions you will get on the HDD.

NOTE: In order to get Windows 10 to boot again as the default, you will probably have to go into UEFI settings and reset the SSD as the first boot device in the boot priority order.

I have finally decided to do a clean installation of windows again. So now my question is:
1 what partition format to use? mbr or gpt?
2 should I format the disk with some third-party software before ?
3 The hdd disk where the system will not be installed, should it also be formatted in the same format as the ssd? Or is this irrelevant?

ppdemo said:

I have finally decided to do a clean installation of windows again. So now my question is:
1 what partition format to use? mbr or gpt?
2 should I format the disk with some third-party software before ?
3 The hdd disk where the system will not be installed, should it also be formatted in the same format as the ssd? Or is this irrelevant?

Assuming that you have no data that you want to keep (such as a separate partition for data only):

1. The USB flash drive that you install Windows from should be MBR partition type, with a FAT32 partition on it marked as active. The internal hard drive/SSD that you want to install to should initially be MBR partition type with no partitions on it at all. It should be 100% unallocated space.

2. Absolutely not. The target HDD/SSD should not have any partitions on it at all during the install. You highlight the "unallocated space" on the hard drive during the install process then click next to let Windows setup create the partitions that it wants.

3. The HDD disk where the system will not be installed should be disconnected during the installation process. This ensures that the system partition the computer boots from will be created on the same drive as Windows is installed to, which is preferred in most circumstances. Then after Windows is installed, reconnect the second HDD/SSD and just for universal convenience, partition it using GPT partitioning. If the drive is over 2TB, GPT is needed to be able to use the entire HDD/SSD.

See this tutorial:
Clean Install Windows 10

NavyLCDR said:

The internal hard drive/SSD that you want to install to should initially be MBR partition type with no partitions on it at all. It should be 100% unallocated space.

previously I used the mbr2gpt command for ssd. I assume then that it is in gpt mode.
I want to install in gpt mode.
so why should the ssd disk be initially in mbr mode?
Another question: By placing the bios in uefi mode, you will directly partition the ssd into gpt mode, right?
Another thing: the hdd never change its partition table, so I assume that it is in mbr, and this is where I have the backup of my data, so I asked if I had to change it to gpt mode or just leave it as is .

ppdemo said:

previously I used the mbr2gpt command for ssd. I assume then that it is in gpt mode.
I want to install in gpt mode.
so why should the ssd disk be initially in mbr mode?
Another question: By placing the bios in uefi mode, you will directly partition the ssd into gpt mode, right?
Another thing: the hdd never change its partition table, so I assume that it is in mbr, and this is where I have the backup of my data, so I asked if I had to change it to gpt mode or just leave it as is .

I recommended MBR initially for the SSD strictly for universal compatibility. The partition type the target drive is going to end up in (MBR v. GPT) depends entirely upon the mode the Windows setup media is booted in. If you boot Windows Setup in UEFI mode, it will "convert" the target drive to GPT. If you boot Windows Setup in legacy BIOS or CSM mode, then it will want the target drive in MBR mode. If you are certain you are going to boot Windows Setup in UEFI mode, then the SSD can just stay in GPT partition type.

Yes, booting Windows Setup in UEFI mode will result in the SSD being partitioned in GPT mode. This is true even if the Windows 10 Setup USB flash drive is MBR - which it should be. This is also true if the SSD is initially in MBR mode, so long as there are no partitions on it. If you boot Windows Setup in UEFI mode, and the SSD is MBR with one or more partitions existing on it, then an error will be generated saying the SSD must be GPT partitioned. But, if the SSD has no partitions on it, then Windows setup will simply convert it to GPT if it is not already.

If the HDD already has data on it and is already partitioned, you can leave it as is. There is no need to have the data HDD partition type match the SSD.

thanks NavyLCDR you have been very helpful! Thank you for your time. luck