Windows 10: Who Knows About GPT v MBR and boot problems?

We have this win10 that won't boot and nothing we've tried will fix it.


Now looking at just reinstalling and windows tell us that it can't reinstall on the available partitions because they are MBR and the computer is an EFI system.


So I know there's a tool mbr2gpt we can use to change the partition type and maybe we will then be able to install a new copy of windows.


But maybe this information throws a new light on fixing the boot problem we've had?


Is there perhaps a new process we can employ to try fit things?


Or is it that perhaps that is \was the very problem? If so how did it get there? For a year or more the computer was working fine.


Are there some viruses or malware that will change your partition type from GPT to MBR?


Such as a WII emulator which was recently installed? Or an overclocking utility?

:)

 

clone MBR HD to bootable GPT partition?

Hi,

1. You cannot convert mbr to gpt without data loss. otherwise, you can follow directions here:

FROM WINDOWS RECOVERY CONSOLE:

To change a master boot record disk into a GUID partition table disk using a command line

• 
  Back up or move the data on the basic master boot record (MBR) disk you want to convert into a GUID partition table (GPT) disk.
  
• 
  Open an elevated command prompt (right-click Command Prompt, and then click Run as Administrator) and type diskpart. If the disk does not contain any partitions or volumes, skip to step 6.
  
• 
  At the DISKPART prompt, type list disk. Make note of the disk number you want to convert.
  
• 
  At the DISKPART prompt, type select disk <disknumber>.
  
• 
  At the DISKPART prompt, type clean.
  

2. I'd suggest converting your vista drive to a virtual machine, load that up on your windows 10 system and use a program like virtualbox to run it.

 

What is a better format for HDD over 2TB Master boot with Win 7 OS RAID... GPT vs MBR?

UEFI -> GPT
BIOS -> MBR

I use GPT whenever possible.

YES! BIOS can only boot MBR.

 

GPT vs MBR boot time and R/W speeds & IOPS?

Not really. UEFI booting from GPT might be slightly faster but I'm sure it's a negligible improvement. It's more of a feature thing. GPT supports more than MBR which is why it's advantageous to use it. I use it because it's the direction partition tables are going and is required to boot via UEFI iirc but, it allows for more partitions and bigger disks.