Windows 10: Convert Windows 10 from Legacy BIOS to UEFI without Data Loss

It´s possible to “convert” the disk back to MBR. For example:

• Boot from a boot UFD with Macrium.
• Create a backup image of the disk in an external USB disk.
• With diskpart, clean the internal disk. This will convert it to MBR.
• Restore the Windows partition.
• Disconnect the external disk.
• Use “Fix Boot Problems” from the UFD to create the boot files in the Windows partition.
• Try a boot.

 

It passed check, and after converting command prompt looked like yours did on the first page of this thread.

BTW i edited my last post after you posted not seeing you had already posted.

 

Thanks will keep this in mind, am still hoping to have gpt. Not sure if it was just in my head but this pc seemed noticably snapier before powering off.

 

Thanks for the help, decided to reinstall to mbr. I followed instructions here

Convert GPT Disk to MBR Disk - Windows 7 Help Forums

to convert back without incident. Will be doing extensive research before ever trying that again.

 

I'm glad you were able to get it sorted DaLee. Thank you for posting back with your results.

Here are some more options for GPT to MBR to help others.

*Arrow Convert GPT Disk to MBR Disk in Windows 10 Windows 10 Hardware Drivers Tutorials

 

thnak you for your thread

 

hi about dual boot warning
i have 3 ssd , with windows 10 , 8.1 and 7
but in every operation system ,i have disabled the ssd in the device manager
i mean for example in w10 ,device manager i have disabled the w8.1 and w7 ssd
to boot in w10 or 7 i use the bios F8
is my case a dual boot ? and the warning in the guide is refering me to avoid the procedure?
and is there a way to convert my w8 and 7 in Uefi?
thanks

 

Hello drugo, *Smile

It's not recommended to use this in a mutiboot OS setup since it would most likely break being able to select an OS at boot. Of course, this also doesn't officially support Windows 7 or Windows 8.

In your situation, you may need to start from scratch installing everything with UEFI to do so.

 

thank Sir Brink !

 

@simrick

*Ditto This will align all partitions as if you do a fresh install. One exception that you do not need to completely clean install. Please look at step 4 of this post:
UEFI Win Clean install using Macrium reflect - Page 2 - Windows 10 Forums

 

I do not see any recent posts by @simrick?

 

Hmmm....the page has been removed?

 

Here it is:

 

Thanks @Brink. Must be I don't have permission to view it then...
And thanks @topgundcp - that's good to know!

 

The thread was removed since the OP was banned for getting abusive in it.