Convert MBR to GPT - MBR2GPT fails with error 0x00000000

Megahertz said:

Managing and playing with partitions is a risky task. Create a drive image before you begin.

To convert the drive from Legacy - MBR to UEFI - GPT your laptop must have UEFI BIOS. If it does, why it didn't came as UEFI - GPT?

Are you sure the Laptop has UEFI BIOS?
...

I bought the laptop in 2014, and pretty early on, I did some imaging tasks. I don't recall all the steps now but I do recall that it was originally in secure boot, and EUFI mode. I had to disable secure boot and enable CSM mode for reasons I can't remember, and it would appear that I inadvertently left it in CSM (BCD) mode ever since; when I noticed this the other day, that's when I decided I really should get it back to EUFI and secure boot.

I was ultimately able to achieve the MBR to GPT conversion using EeaseUS Partition Master. After that, I changed BIOS to EUFI and the machine booted fine. The only thing that doesn't work properly, now, is the 'advanced recovery' mode in windows. Previously, I could go to settings / Update and Security / Recovery / Advanced Startup / Restart now, and upon restart, it would offer Continue / Troubleshoot / Turn off your PC, and the 'Troubleshoot' would offer 6 options including command prompt. Now, Troubleshoot only offers 'startup settings' and 'UEFI Firmware Settings'. But I can live with this!

Thanks everyone for their help!

SIW2 said:

Probably the simplest way is Delete the samsung 16gb partition.

If it has the original win8 image it is unlikely you want it and your F4 is no longer working. Geeky types might clone it to a spare disk to play with.

I expect diskgenius would do the job as is, but it is simpler for beginners to get rid of that samsung_rec partition and then see if mbr2gpt stops complaining.

out of curiosity, what is the partition ID of that samsung_rec ?

I did try deleting the Samsung_rec partition, thinking that would be the solution, but that set me back a step in that MBR2GPT failed validation again. So getting rid of the 100 MB partition was the furthest I ever got with mbr2gpt.

Sorry for being dumb, but how do I tell the 'partition ID' of the samsung_rec partition?

Megahertz said:

Open a CMD window as administrator and type:

diskpart
select disk 0
list part (take note of the Samsung Recovery partition number)
select part n (replace n with the partition number identified above)
detail part
exit

Result:

Code:

Partition 3
Type    : ebd0a0a2-b9e5-4433-87c0-68b6b72699c7
Hidden  : No
Required: No
Attrib  : 0X8000000000000000
Offset in Bytes: 1029870452736

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
* Volume 1         SAMSUNG_REC  NTFS   Partition     16 GB  Healthy

DISKPART>

I don't see 'Partition ID'. Are you referring to the 'Type' string?

Steerpike58 said:

Now, Troubleshoot only offers 'startup settings' and 'UEFI Firmware Settings'. But I can live with this!

Thanks everyone for their help!

If you fix the recovery sequence you will get the extra options.

reagentc /info

to see the current state.
--------------------------------------------------------------------------------

too late to check the samsung_rec partition id now. Had to be done before converting, now we will never know what it was. Of course after converting the disk with a 3rd party tool it now shows as ms basic data partition.

SIW2 said:

If you fix the recovery sequence you will get the extra options.

reagentc /info

to see the current state.
--------------------------------------------------------------------------------

When I type 'reagentc /info' I get

Code:

C:\Windows\system32>reagentc /info
Windows Recovery Environment (Windows RE) and system reset configuration
Information:

    Windows RE status:         Disabled
    Windows RE location:
    Boot Configuration Data (BCD) identifier: 45e8c8ee-172f-11eb-8361-b160c29486b6
    Recovery image location:
    Recovery image index:      0
    Custom image location:
    Custom image index:        0

REAGENTC.EXE: Operation Successful.

Looks like it still thinks it's sitting on a BCD disk ...?

SIW2 said:

too late to check the samsung_rec partition id now. Had to be done before converting, now we will never know what it was. Of course after converting the disk with a 3rd party tool it now shows as ms basic data partition.

I'll be re-imaging my second identical laptop shortly so will figure that out. Thanks!