MBR to GPT


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Back when they gave Windows 10 away for free as an upgrade, I did that. Upgraded my Windows 7 to Windows 10. At the time my disks were/are MBR. I just clean installed Windows 10 on my drive and wanted to convert it to GPT. I tried the MBR2GPT command line tool but it failed for some reason. Both drives are in MBR as I checked. Trying to do this without losing data or having to spend money on third party software, which won't work without paying. Thanks
 
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several things might be needed.
1. Turn off WinDefender or any AV you are using.
What error method
2. MBR2GPT.EXE is located in the Windows\System32 directory on a computer running Windows 10 version 1703 (also known as the Creator's Update) or later. The tool is available in both the full OS environment and Windows PE. To use this tool in a deployment task sequence with Configuration Manager or Microsoft Deployment Toolkit (MDT), you must first update the Windows PE image (winpe.wim, boot.wim) with the Windows ADK 1703, or a later version.
(Not sure what method you used) if from WinPE or driectly from Windows.
3.

  1. Back up or move the data on the basic MBR disk you want to convert into a GPT disk.
  2. Open an elevated command prompt by right-clicking Command Prompt and then choosing Run as Administrator.
  3. Type diskpart. If the disk does not contain any partitions or volumes, skip to step 6.
  4. At the DISKPART prompt, type list disk. Note the disk number you want to convert.
  5. At the DISKPART prompt, type select disk <disknumber>.
  6. At the DISKPART prompt, type clean.
    Note
    Running the clean command will delete all partitions or volumes on the disk.
  7. At the DISKPART prompt, type convert gpt.

Table 1
ValueDescription
list diskDisplays a list of disks and information about them, such as their size, the amount of available free space, whether the disk is a basic or dynamic disk, and whether the disk uses the Master Boot Record (MBR) or GUID Partition Table (GPT) partition style. The disk marked with an asterisk (*) has focus.
select disk disknumberSelects the specified disk, where disknumber is the disk number, and gives it focus.
cleanRemoves all partitions or volumes from the disk with focus.
convert gptConverts an empty basic disk with the Master Boot Record (MBR) partition style into a basic disk with the GUID Partition Table (GPT) partition style.

 
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Count me as 13 years out of date since I retired. My machines in this house are all good 'ol MBR. ( not counting the raspberry Pi and the NAS which are file system Int4) why would I want to change? I guess that if I bought a new machine it would be GPT?
 
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As long as the GPT drive is not the Boot drive, you should not have any problems. However, if it is, Your BIOS has to support it and needs to be set up accordingly, meaning not as legacy drives (MBR). Don't know the exact terminology as I do not use GPT...
 
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If I read your solution using diskpart, this will wipe both of my disks? There has to be a way to do this without doing that.

Now I tried the AOMEI Partition Assistant but when I click on the click on the Convert to GPT I received the following pop up:

1587858696729.png

Not sure why it is saying my System partition and boot partition are on different disks because they aren't. My C drive (Windows) is on its own disk separate from my program disk, which has everything else.
 
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OK then i recommend you DL and test MiniToolPartition, for me it seems the simplist for use by "My Clients"
and if your System and Boot are not on the same HDD, that does make it rather difficult to do. but
You need to be 100% sure where the BOOT Part is, then make room for the System (OS), to move it to the Boot Part HDD.
easy to do for me, but im not sure,,,,so make a image of only the System (OS), then make a partition which is slightly larger than, boot to WinPE disk, then restore the Image (OS) the the new partition where the Boot Part is also located. make no difference what the Drive letter is, you can change it. when the image of System and Boot is on the same HDD, make sure the System is now C:
next you should be able to restart and boot normally, since the Boot Part HDD will also contain the OS part. Dism commands , BCDEdit commands, and the program which you use to make and restore the OS, should work.

I also have some clients, make a image of only C:\ (System) then do a Clean Install of so that Boot, Rec, and OS are the same location, then boot back and restore you original C: to the new C: . and I have never seen AOEMI or any other Image Program tell you that the are seperate when they are not... I have seen many time unknowly people change so that Boot and System are on seperate HDDs.
Make your image first and save on a total seperate so you do not loose anything.
 
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So, here is a screen shot of my Disk Management. Disk 1 is my C drive with System Reserved and not sure what Disk 1, Part 3 & 4 are. Disk 0 or D Drive has all my programs on it. So, everything to do with Windows is on Disk 1. Not sure why it states my System Part and Boot Part are on two different drives. F & G drivers are externals.

1587930176873.png


FYI, this is a clean install on Disk 1. I formatted the drive during Windows install.
 
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yes so much for disk management it does not show all the partitions. but MiniPartitionTool will and it is FREE.
Disk 3 is my Boot Drive and System Drive.
MiniToolPart
1587933016667.png

Disk Management - Disk 2 is the same as Above.
1587933141862.png


and it does show different -
now to see exactly where the Boot Part is
BCDEDIT show Disk 2
C:\WINDOWS\system32>bcdedit

Windows Boot Manager
--------------------
identifier {bootmgr}
device partition=\Device\HarddiskVolume2
path \EFI\MICROSOFT\BOOT\BOOTMGFW.EFI
description Windows Boot Manager
locale en-US
inherit {globalsettings}
flightsigning Yes
default {current}
resumeobject {d1627dba-84d5-11ea-bd5e-7085c2da9da4}
displayorder {current}
toolsdisplayorder {memdiag}
timeout 0
displaybootmenu Yes

Windows Boot Loader
-------------------
identifier {current}
device partition=C:
path \WINDOWS\system32\winload.efi
description Windows 10
locale en-US
inherit {bootloadersettings}
recoverysequence {1573e9ee-84d6-11ea-bd60-f88b15520cd5}
displaymessageoverride Recovery
recoveryenabled Yes
isolatedcontext Yes
flightsigning Yes
allowedinmemorysettings 0x15000075
osdevice partition=C:
systemroot \WINDOWS
resumeobject {d1627dba-84d5-11ea-bd5e-7085c2da9da4}
nx OptIn
bootmenupolicy Standard

C:\WINDOWS\system32>
 
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well for one it shows D: is your System drive. while c: should be your system drive.
please look at mine again.
1587937661175.png
 
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I find it odd that disk managment, in snuffy's picture, is not showing the unallocated space, ?but seems to have included it within C. The computers I have to hand all show it separately .??
Otherwise, the (built in) disk management should show the same as the third party utility. The last two partitions are shown, but for some reason only the size, possibly in another type format.
 
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I'm there with you now and it makes no sense for my D drive or Disk 1 to be system. That drive has never had Windows installed on it either when I had Win 7 or with Win 10. I'm sure I may not like the answer but what do I need to do to fix it where by Disk 2 (C drive) is both System and boot?
 
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Disk 0, 1, 2, etc is determined by what SATA port drive is attached to.
You want boot drive attached to fastest port.
Usually, only one or two ports are SATA III.
Use HWiNFO to display port & drive transfer speeds.


BTW, MBR only allows 3 Primary partitions, the remaining are Logical.
GPT allows 128 Primary partitions.
GPT requires a UEFI BIOS.
Windows 7 would not fresh install to a GPT drive. If you upgraded to Windows 10, it's still MBR.
GPT supports disks larger than 2 TB in size while MBR cannot.

 
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Oh boy, did I have fun converting my boot drive from MBR to GPT! It took me a few weeks of reading many lengthy topics here and elsewhere. But finally I was ready to use Macrium Reflect. I had tried many tools, but in the end all I used was WinPE and Macrium Reflect.
My problem started when I discovered that Windows 10 monthly updates had failed for a few months. I found out that the problem might be because of MBR. At this point I did not even understand MBR and GPT, but started to wonder if my excessively long boot time, 25 seconds with a Samsung 850 SSD might be improved with GPT.
MBR2GPT refused to do the job. More lengthy threads convinced me that I needed to wipe the drive and start fresh. Here's what I did:

  1. Just follow MS advice: https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/configure-uefigpt-based-hard-drive-partitions
  2. Then move over to Macrium and restore the C drive image: https://kb.macrium.com/KnowledgebaseArticle50151.aspx.
  3. Finally fix the boot partition: http://kb.macrium.com/KnowledgebaseArticle50168.aspx .
I ended up with more than one boot choice. I can't recall what I did to fix that, but one of the boot choices was wrong and eventually I got rid of it.

My notes from that time have more detail:
  1. Use Macrium to make image of C drive OS partition.
  2. Reset the BIOS. Open case, move the MB BCLR jumper from pins 1,2 to pins 2,3 for 15 seconds. Restore to 1,2.
  3. Can I get into BIOS? Change from CSM to UEFI.
  4. Reboot.
  5. If WIndows 10 OK, then again backup with Macrium.
  6. Now boot into WinPE USB or DVD.
  7. Use DISKPART to wipe the C drive (see step #1 about MS advice).
  8. Reconstruct with GPT partitions.
  9. Reboot into Macrium rescue disk.
  10. Copy C drive image to the OS partition.
  11. What about BOOT partition?
 
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One reason why I'm not using GPT. I've not paid for some of the GPT features of partitioning software. I converted to GPT RAID volume once and ran into issues. I had to erase the whole volume to convert back to MBR. After that I decided to just stay with MBR. One day I will be forced to go GPT. But for now I'm happy on MBR.

TLDR: If GPT is going to include a royalty fee for usage, I can wait.
 
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Since I don't use large drives [over 1TB] for booting I don't notice much performance difference between MBR and GPT. My newest Desktop is nearly 4 years old with a 1TB HDD using UEFI and even it is split 150GB for C: [boot] and D: for Data. My other Desktops are older with smaller drives, largest of the bunch at 500GB.
 
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Back when they gave Windows 10 away for free as an upgrade, I did that. Upgraded my Windows 7 to Windows 10. At the time my disks were/are MBR. I just clean installed Windows 10 on my drive and wanted to convert it to GPT. I tried the MBR2GPT command line tool but it failed for some reason. Both drives are in MBR as I checked. Trying to do this without losing data or having to spend money on third party software, which won't work without paying. Thanks
The first step in switching is to backup all data and clean the drive on windows 10
 

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