How to convert Hard Disk to UEFI Hard Disk

[Explosion0]

So I was rushing through installing windows on a buddies computer and for some reason after the initial install it didn't boot but went back to the install (probably just because I didn't switch boot drives) and so I reformatted and tried to do a second install but said it wasn't allowed giving me the error: Windows cannot be installed on this drive. The selected disk is of the gpt partition style. So after checking and and cleaning disk through a second computer it still wouldn't install. So I looked closer at the drive in the BIOS and its appeared to not have a UEFI tag by it (see attachment) and so after doing a little research you need UEFI partitioned with GPT style to install windows. So is there a way to convert the drive back to UEFI or has it been corrupted by my ignorance?

[Master Disaster]

Before doing anything head into BIOS, find the setting for CSM and disable it then shut down the PC.

 

1) Unplug/remove all drives except the one you want Windows on (this is important, don't skip it)

2) Boot the Windows installer

3) Click next till you reach the partition screen

4) Press Shift + F10

5) Type "diskpart" and hit enter

6) Type "select disk 0" and hit enter

7) Type "clean" and hit enter

8 ) Type "convert GPT" and hit enter

9) Type "exit" and hit enter

10) Close command prompt

11) Click next, do not try to partition or format the drive yourself, let Windows handle it automatically

12) Once Windows has installed, shut down and reconnect any other HDDs/SSDs

[Guest]

Be sure CSM is disabled and UEFI is enabled. F10 save restart. 

Can try secure boot and set OS type to UEFI Mode

[TheTechDudeYT]

Howdy there partner,

 

Converting back to MBR is not too hard.

 

If you have your Windows install disk, go ahead and boot into it.

 

When you boot in, open command prompt by holding down your Shift + F10 key. We will be using Command Prompt to run some commands.

 

In command prompt, type the command “diskpart” in and press enter.

DiskPart is the tool built into Windows so we can format and convert from GPT.

 

Once you’ve gotten into diskpart, you need to locate your drives. This is really simple. Type “list disk” and all of your drives should appear.

 

If you have one drive, it should show up as disk 0, but it can differ computer to computer.

 

Once you’ve located your disk, you need to tell diskpart which drive to use to complete the rest of the commands. 

Type in “select disk X” (x would be your drive number)

 

After you type that in and press enter, you should get a line of text saying “Disk X is now the selected disk”

 

Great, now we’re ready to clean the drive again so we can change it to MBR.

 

First, you will need to clean the drive by simply typing “clean”. You will get a line of text saying “DiskPart succeeded in cleaning the disk.”

 

After that, now you will convert to MBR. Simply type “convert mbr” and press enter. You will get a line of text saying “DiskPart successfully converted the selected disk to MBR format.”

 

Tada! That’s it for converting, however we still need to make a partition and give the drive a file format.

 

This too is quite simple, simply type “create partition primary” and once again it will give you a line saying it succeeded.

 

We need to flag that partition as active now, so simply type “active” and it will once again show it succeeded.

 

Now we need to make the drive have a file system. To do this type the command “format fs=ntfs quick” and that should succeed. 
 

That’s it! Now just go through the Windows Installer again and you should be good to go!

 

Hope this helps,

Daniel

 

[Eigenvektor]

Just now, TheTechDudeYT said:

Converting back to MBR is not too hard.

Unless he has a computer with a BIOS (instead of UEFI) this is not what he wants to do.

 

Most likely the computer has CSM (Compatibility Support Module) enabled, which means the installer thinks it is on a system with a BIOS and requires MBR. Instead CSM should be disabled, so the installer correctly detects UEFI and allows to install on a GPT partition.

[Master Disaster]

1 minute ago, TheTechDudeYT said:

Howdy there partner,

 

Converting back to MBR is not too hard.

 

If you have your Windows install disk, go ahead and boot into it.

 

When you boot in, open command prompt by holding down your Shift + F10 key. We will be using Command Prompt to run some commands.

 

In command prompt, type the command “diskpart” in and press enter.

DiskPart is the tool built into Windows so we can format and convert from GPT.

 

Once you’ve gotten into diskpart, you need to locate your drives. This is really simple. Type “list disk” and all of your drives should appear.

 

If you have one drive, it should show up as disk 0, but it can differ computer to computer.

 

Once you’ve located your disk, you need to tell diskpart which drive to use to complete the rest of the commands. 

Type in “select disk X” (x would be your drive number)

 

After you type that in and press enter, you should get a line of text saying “Disk X is now the selected disk”

 

Great, now we’re ready to clean the drive again so we can change it to MBR.

 

First, you will need to clean the drive by simply typing “clean”. You will get a line of text saying “DiskPart succeeded in cleaning the disk.”

 

After that, now you will convert to MBR. Simply type “convert mbr” and press enter. You will get a line of text saying “DiskPart successfully converted the selected disk to MBR format.”

 

Tada! That’s it for converting, however we still need to make a partition and give the drive a file format.

 

This too is quite simple, simply type “create partition primary” and once again it will give you a line saying it succeeded.

 

We need to flag that partition as active now, so simply type “active” and it will once again show it succeeded.

 

Now we need to make the drive have a file system. To do this type the command “format fs=ntfs quick” and that should succeed. 
 

That’s it! Now just go through the Windows Installer again and you should be good to go!

 

Hope this helps,

Daniel

 

Great instructions but OP would want GPT over MBR on a system that is capable of UEFI boot mode otherwise fastboot & secure boot will not work.

[WhitetailAni]

5 minutes ago, Eigenvektor said:

...which means the installer thinks it is on a system with a BIOS...

Show me a modern computer without a BIOS.

Note that I don't count UEFI as no BIOS - it is basically the same thing with better looks and features. 

[Master Disaster]

1 minute ago, ragnarok0273 said:

Show me a modern computer without a BIOS.

Note that I don't count UEFI as no BIOS - it is basically the same thing with better looks and features. 

It really isn't. Technically UEFI replaced BIOS. the fact UEFI needs a compatibility mode for legacy booting at all shows how different the two are.

[WhitetailAni]

It has that functionality though.

[Eigenvektor]

1 minute ago, ragnarok0273 said:

Show me a modern computer without a BIOS.

Note that I don't count UEFI as no BIOS - it is basically the same thing with better looks and features. 

That's really not the point. On a modern system with UEFI, GPT should be preferred over MBR is all I'm saying. Whether UEFI and BIOS are the same or not doesn't really matter.

[Master Disaster]

Just now, ragnarok0273 said:

It has that functionality though.

I mean, an Airbus A320 has the same functionality as an F22 Raptor but you wouldn't say they are the same thing.

[Explosion0]

Thanks for the help Master Disaster! Had to restart again after following your instructions because it seemed to think there was a small partition left on the drive but after restarting it worked as intended.