Windows 10 Pro cannot boot after converting MBR to GPT

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DzigiBau

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Joined
Mar 29, 2025
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6
Guys,

Please help. I have dual boot system, Windows 11 and Windows 10 on separate SSD disks.

I recently changed my hardware and everything was fine, both Windows booted all right in MBR disks scenario and Legacy Boot. After I changed MBR to GPT and made changes in BIOS, CSM disabled and Secure Boot on, created EFI partitions on both disks with BCDEdit commands, I can boot Windows 11, it just disabled WinRe partition, which I enabled by CMD commands and putting GPT IDs to partition with recovery, but I could not boot Windows 10. It start booting, Windows logo, spinning circles and after it comes to the point where login screen should appear, it stays with black screen with cursor I can move around. I cannot reach WinRE in Windows 10, since MBR to GPT conversion disabled Recovery partition on SSD where Windows 10 is installed.

First thing I check for viruses, no viruses on complete system, checked with Malwarebytes. Then I created USB installation for the same version of Windows 10 Pro I have, using UUP damb, version from January, when my Windows 10 was last updated. It is version with wim file, and it has only one index:1 which is for Widnows 10 Pro.

I tried several Dism scenarios with mounted USB disk, went to CMD, tried DISM offline scenarios and in ScanHealth gives me meesage that Component Store is corrupted but reparable and after that RestoreHealth went to 100% and said that cannot find "Source" to perform operation, althugh my source is USB installation disk I created for the same version fo Windows 10. SFC commands: SFC /SCANNOW /OFFBOOTDIR=X:\ /OFFWINDIR=X:\WINDOWS stops and show famous error: "Windows Resource Protection could not start the repair service". I changed letter X to specific letter of my SSD drive with Windows 10, which I saw after used command Diskpart, Lis vol.

That far I have gone here.

Could you please help me to make Windows 10 bootable again, I have specific and paid software which cannot be used in Windows 11. Something little bit old, but it works here. I know reinstallation is one of final solutions, but I need to repair this Windows and keep my installed apps if it is possible.

​

 

Attachments

Last edited:
DzigiBau said:
I know reinstallation is one of final solutions, but I need to repair this Windows and keep my installed apps if it is possible
Click to expand...
You can still accomplish this.


If you accomplish the above, please consider a backup plan. Having a valid backup of your drives will eliminate these problems moving forward.
 
Thank you @xrobwx71.

I know these scenarios. First one speaks about Windows 10 In-Place Upgrade, which can be done from booted Windows and reinstall it with keeping all installed apps and files. My Windows cannot boot and that scenario is not possible.

The other one is clean installation of Windows 10, and creation of Windows.old folder of previous installation, but that would not keep installed apps I require here, which means that I need to reinstall all apps and return back their settings which is a lot of job to be done. Maybe whole day.

That is why, I am asking for eventual solution to repair Windows 10, which worked in MBR, Legacy situation, but it will not boot up in GPT, UEFI scenario. I watched a lot of videos with DISM and SFC commands, but somehow I cannot do it here, which I explained in my first post. Thank you very much for your suggestion, but I need one to repair existing Windows 10 Pro if anybody knows how I would appreciate a lot to be shared here.
 
There is a portion of the video that shows booting from a USB drive, going through the install, and picking the partition that has Windows on it. Install to this portion, boot into Windows and the personal files and apps are still there.

That being said, can you get to an elevated command prompt? Have you tried the bootrec /fixboot ?

If that doesn't work, go here and try this:
Once you click the link, Start here:

  1. Rebuild Boot Configuration Data (BCD)​

 
Last edited:
xrobwx71 said:
There is a portion of the video that shows booting from a USB drive, going through the install, and picking the partition that has Windows on it. Install to this portion, boot into Windows and the personal files and apps are still there.

That being said, can you get to an elevated command prompt? Have you tried the bootrec /fixboot ?

If that doesn't work, go here and try this:
Once you click the link, Start here:

  1. Rebuild Boot Configuration Data (BCD)​

Click to expand...
Thank you xrobwx71.

First method I watched carefully and it is last resort. Installation of Windows 10, using Custom option will install Windows 10 and create Windows.old folder with my files, but apps needs to be reinstalled as far as I know. That requires a lot of time.

Regarding second option. I have Windows 11, on Disk 0, with boot partition C:\Windows and it boots correctly. I have dual boot system and my Windows 10 is on Disk 2, partition I:\Windows. I manually created EFI partitions on both disk, using BCDedit commands and giving them necessary IDs. Disk 1 is used for apps installed with Windows 11, all apps for Windows 10 are on the same Disk 2, no additional partitions, just one for Windows 10 and for all installed apps.

Windows 11 boots all right, but Windows 10 start booting, I have Windows logo, spinning circles, no errors and when it comes to login screen, it does not show up, it stays on black screen where I have cursor I can move around. Is it bootrec problem, since I tried to fix it using USB installation media, open CMD and tried several DISM and SFC commands which showed me error that Component store is corrupted and it is reparable? How to repair Component stote to make Windows 10 boot again? I uploaded dism log file after I saw this error about Component Store corrupted and reparable, but I do not know how.

Both disks are now GPT and should boot in UEFI mode. How can I repair my Windows 10 Pro to boot again? It booted correctly when it was in MBR, Legacy mode, but after I converted it to GPT as I did for Windows 11 which continue to boot all right, I cannot boot Windows 10 in GPT UEFI mode. Changing BIOS for Legacy mode, does not change anything, Windows 10 stays un-bootable. Do you have some instructions how to make it boot again in GPT UEFI mode, please?

I can boot with USB installation media, with Windows 10 version completely same as I have.
 
DzigiBau said:
How to repair Component stote to make Windows 10 boot again? I uploaded dism log file after I saw this error about Component Store corrupted and reparable, but I do not know how.
Click to expand...
@Maxstar

Let me get you some help. I have no training in manipulating the Component store. Maxstar does.

When you were in the command prompt and ran the DISM, SFC and BCedit switches were you cd'd (change directory) into the correct partition?

If you are in PE (Windows Preinstallation Environment), you might have to use the DISKPART function. Then LIST. Find the partition with the correct Windows installation and go from there.
 
xrobwx71 said:
@Maxstar

Let me get you some help. I have no training in manipulating the Component store. Maxstar does.

When you were in the command prompt and ran the DISM, SFC and BCedit switches were you cd'd (change directory) into the correct partition?

If you are in PE (Windows Preinstallation Environment), you might have to use the DISKPART function. Then LIST. Find the partition with the correct Windows installation and go from there.
Click to expand...

Yes, I always start with Diskpart to check exact volumes and partitions. Then, I use DISM command for offline repair: Dism /Image:I:\ /Cleanup-Image /RestoreHealth /Source:wim:J:\sources\install.wim:1 /LimitAccess where I:\ is my Windows 10 partition and J:\ is USB installation disk, index: 1 is for Pro version, which I prepared with UUP Dumb commands for the same version of Windows 10 Pro I have, but it gives me error that Source cannot be found.

If I use ScanHealth command, I get Component Store is corrupted and repairable, which can be done with RestoreHealth command, but I did not have success so far. If I use command: SFC /Scannow /OffBootDir=I:\ /OffWinDir=I:\Windows it gaves me error: Windows Resource Protection could not start the repair service. I am sorry for saying that I used BECDEdit, since I used BCDBoot command: bcdboot I:\windows /s v: /f UEFI where v:\ is partition created for EFI System Partition, I gave 900Mb of space, since I have Dual Boot system and it need little bit more space than 100Mb.

I also tried chkdsk I: /f /r to check disk for errors, there were no errors at all. After everything, I got stuck with this Component Store is corruped and rapairable, which I do not know how to solve. If you could or if @Maxstar could help, I would be grateful.
 
Oops, I've missed the attachement in the first post, and there are a lot of files missing / corrupt (1911).

Did you make backups before the MBR to GPT conversion?
 
Maxstar said:
Oops, I've missed the attachement in the first post, and there are a lot of files missing / corrupt (1911).

Did you make backups before the MBR to GPT conversion?
Click to expand...
I did not. Since I have Dual Boot system, Windows 11 and Windows 10, on two separate SSD disk, I thought it should be all right. Windows 11 booted all right, without any problem but I needed to reinstall my chipset drivers again and I have never succeeded to boot Windows 10. What I tried also is to copy WinSxS folder from USB installation disk to Windows folder, but situation remain the same. The folders, DISM sees as missing are existing in USB installation disk, which I used for "Source" part of DISM command. I check that and all folders and dll files, which DISM says they are missing, actually exits on USB installation disk. SFC Command has always reported the same error: Windows Resource Protection could not start the repair service. Could you help me please?
 

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