Convert GPT to MBR

[johnrobert]

Cloned to SSD on Win 10 desktop GPT. I want to use it on an older desktop that does not support GPT Tried converting to MBR from the link below
I did it with a USB SATA adapter it said converted successfully, but drive is no longer detected in windows and it won't boot.
the clone booted on original computer before conversion to MBR
it is full of legacy programs so don't want to do a clean install
Is there a better way of doing it

 

[NviGate Systems]

Manually backup the HDD using imagex then restore to the new HDD after manually partitioning it. You will need to remember to "active" the drive when using diskpart and after you need to run bcd to update boot options.

 

[johnrobert]

Thanks
I remember doing this making an OSX boot disk and making it active, he left that important part out of the video

 

[NviGate Systems]

Also, his video shows cleaning drive first, aka erasing it, so I hope you still have a backup if you followed the video step by step.

I don't trust these videos, they are made by "bros" who want likes/etc and the title is misleading, he is erasing and repartitioning a drive. He's not converting anything.

 

[Sky-Knight]

You cannot convert GPT to MBR, you can only wipe the drive and start over.

In fact, that's EXACTLY what that "tutorial" about "conversion" does.

It opens diskpart, selects disk 1, CLEANS it.... which WIPES THE PARTITION TABLE AND ALL DATA. Then runs the convert command to select an MBR partition type.

Documentation is here: https://docs.microsoft.com/en-us/wi...management/change-a-gpt-disk-into-an-mbr-disk

You can change a disk from a GPT to an MBR partition style as long as the disk is empty and contains no volumes.

So... if you thought you were going to save what's on that disk, it's already over... as soon as you pressed [enter] after inputting "clean", all data was destroyed.

 

[johnrobert]

it was the cloned disk so it does not matter, thanks for clearing it up

 

[Joep]

You cannot convert GPT to MBR, you can only wipe the drive and start over.

In fact, that's EXACTLY what that "tutorial" about "conversion" does.

It opens diskpart, selects disk 1, CLEANS it.... which WIPES THE PARTITION TABLE AND ALL DATA. Then runs the convert command to select an MBR partition type.

Documentation is here: https://docs.microsoft.com/en-us/wi...management/change-a-gpt-disk-into-an-mbr-disk



So... if you thought you were going to save what's on that disk, it's already over... as soon as you pressed [enter] after inputting "clean", all data was destroyed.

Well you can IF you meet some conditions such as size of drive/partitions, number of partitions. You could probably use DMDE to do it.

Remember partition tables are just pointers to areas on a drive. If number of partitions does not exceed 4 (as we need 16 bytes for one partition, and we have 64 bytes available), drive does not exceed 2 TB (and nor do partitions) you can accommodate them inside a standard MBR partition table.

If you want it is verse 2. This strictly partition tables side of the story and I have done this over a decade ago. How a modern OS handles this, whether you need to fiddle with boot code in MBR or partition boot sectors, I haven't got the foggiest idea.

 

[mikeroq]

Good lord how old is this computer that it doesn't support GPT?

Hard drive tools/cloning software like Paragon Hard Disk Manager can convert between MBR and GPT. Some will even fix the Windows bootloader for you too. I've done this a few times.

 

[Joep]

Cloned to SSD on Win 10 desktop GPT. I want to use it on an older desktop that does not support GPT Tried converting to MBR from the link below
I did it with a USB SATA adapter it said converted successfully, but drive is no longer detected in windows and it won't boot.
the clone booted on original computer before conversion to MBR
it is full of legacy programs so don't want to do a clean install
Is there a better way of doing it

When using a SATA > USB adapter you must make sure it does not change sector size from 0.5 KB to 4 KB. If that happens while native block size is .5 KB and you use that to mess with partition tables of existing volumes, you're asking for trouble.

 

[MudRock]

You can convert GPT to MBR. Not sure how you ended up starting GPT and then it doesn't behave unless you're moving to older hardware?

You'll likely have to rebuild the boot info too.

I usually use MiniTool Partition Wizard for the convert, then your bootrec/bootsect/bcdboot commands. Search here for bootrec and there's a few tutorials. This is okay, but somehow off the top of my head I think its missing something

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