Convert GPT Disk to MBR Disk in Windows 10  

pxfragonard said:

Does the MiniTool Partition Wizard Free without Data Loss install McAffee? It seems that's what it says.

Normally it doesn't, but you should always pay attention to the setup menu to make sure nothing is selected by default to install along with the program.

ritjesman said:

Shawn - thank you for all the great tutorials down through the years both here and at Seven Forums. They've been enormously helpful.

I really think you should make the Data disk focus explicit in the thread title and add a warning at the top reinforcing that the various covered approaches are for Data disks only and using them on an OS disk is high risk and can result in not only a non-bootable computer but also a non-recoverable boot drive without access to an alternate boot mechanism (like bootable recovery USBflash drive).

I used the MiniTool Partition Wizard approach (the free version of the EaseUS tool does not support GPT to MBR). Like @anctop I attempted to convert an OS drive. As stated above making partition changes to the boot partitions must be completed between the Starting Windows and Welcome/Login steps in the boot process. In my case (like for anctop) it resulted in a boot error with "No OS found message" when restarting.

I wasn't as smart as anctop so when I got that message instead of setting the boot partition to Active with diskpart I tried to revert to a bootable state (I use Macrium Reflect) with following progression:

1. attempted to restore the most recent verified backup (a fresh updated/activated install) with GPT scheme: on restart got the two blinking cursors but boot would not progress to Starting Windows
2. attempted to restore a Win7 MBR image: on restart got the two blinking cursors but boot would not progress to Starting Windows
3. used the Reflect recovery capability to Fix Boot Problem: despite a Successful Update of boot files message the system would still not progress to Starting Windows

I've never had a disk image restore fail to result in bootable condition. I've done a bit of experimentation in my OS (in the MBR world) but always with the confidence that reverting to a stable bootable state was only an image restore away; suffice to say this was quite a nasty surprise.

The fix was to boot using the Win10 recovery Toolkit USB and Clean the disk using diskpart so the entire disk was unallocated. After that the Reflect restore worked as advertised.

Certainly this appears to be a problem with Reflect's restoration process but it illustrates how badly things can go awry if the GPT to MBR conversion process is applied to a live OS.

Sorry to hear the trouble you went through.

I added a warning to help others avoid doing the same.

I just installed a 1TB Crucial SSD in my desktop PC to be used for programs & data storage - not the OS which is on another SSD.

I initially set it up using the default settings in Disk Management which shows it has a GPT partition as below. I noticed all my other HDD storage disks have MBR partitions.

Is there any particular advantages in using GPT for data disks and are the any performance differences between MBR & GPT?
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Steve C said:

I just installed a 1TB Crucial SSD in my desktop PC to be used for programs & data storage - not the OS which is on another SSD.

I initially set it up using the default settings in Disk Management which shows it has a GPT partition as below. I noticed all my other HDD storage disks have MBR partitions.

Is there any particular advantages in using GPT for data disks and are the any performance differences between MBR & GPT?
Attachment 315145

Hello Steve,

The info and links at the top of the tutorial can help to compare MBR vs GPT, but GPT is a newer more reliable standard and supports larger and more partitions.

One possible drawback is GPT can only be used with 64-bit Windows using UEFI.

I'm not aware of any performance differences since that is mostly limited to the HDD's or SSD's rating instead.