[SOLVED] Bootmgr is missing even after clean reinstall of windows 10

DragonGunner

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Apr 4, 2014
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Hi and happy holidays! I recently upgraded large parts of my computer for Black Friday. With these changes came the addition of two new ssds, one of which replaced my boot drive. I cloned the old c: (ssd) and everything worked fine. For a day. Then this morning I turned on my computer and it said boot manager is missing.

I've spoken at length with a Microsoft agent and they initially directed me to use bootrec command lines to repair MBR and fix boot - the latter of which did not work (denied access). Then tried in the winpe environment for installation of Windows to repair startup, which also didn't work. Looked at the drive through my EaseUS boot able thumb drive, and the format is now Raw.

Had lots of difficulty installing Windows 10 on the C: ssd, or for that matter anywhere else. I was eventually told to format my original C drive and reinstall Windows onto it, which I did. Imagine my shock when I turn on my computer again (with only that drive connected) and boot manager is still missing. I can still boot from the older, smaller ssd that I had used for the windows install. All drives are recognized by bios.

What went wrong?

My old parts are in my signature below. New ones as follows: 2x Crucial 2TB SSD, Gigabyte Aorus Wifi Pro, i7-9700k, 1x16GB T-Force Vulcan C ddr4 3200. Running windows 10 home, but upgraded a few weeks ago, before the hardware upgrade. It may also be worth noting that the drives replaced by the new ssds were dynamic drives and had to be cloned rather than copied.

As always, all input is enormously appreciated.
 
Solution
Run chkdsk on G: drive
chkdsk /f G:

If that doesn't fix RAW file system, then you'll have to reinstall or perform cloning.
Before install or cloning clean disk 2 with diskpart.
diskpart
list disk
select disk 2
clean

Disconnect all other drives if you decide to reinstall. Leave only one drive connected.
Try different boot sequence settings until you can boot into windows.

Then show screenshot from Disk Management.

What are model names of the drives? Any of them M.2 ?

Side note - single ram module limits memory performance to single channel mode (memory bandwidth is essentially cut in half).
 
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DragonGunner

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Impropper cloning most likely.
Try different boot sequence settings until you can boot into windows.

Then show screenshot from Disk Management.

What are model names of the drives? Any of them M.2 ?
No, no M.2. I played with bios and it's recognizing drives and letting me boot with the old ssd again, but not the new one.

Idk about the clone - I did it with a easeus winpe instance, and it worked fine initially. Now [the new ssd is] not working even after a format and reinstallation of windows.
 

DragonGunner

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Apr 4, 2014
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The C: drive is what I'm currently booting from - the old SSD. G: is the new SSD with its clean installation of Windows 10. Both G: and E: are the new SSDs: Crucial MX500 2.5" 2TB SATA III 3D NAND Internal Solid State Drive (SSD) CT2000MX500SSD1. E: is working fine, games are loading no problem.

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Ok. This is, how you fix it. Execute from elevated command prompt. Regular command prompt will give error on last step.
If you get any errors, then stop immediately.

diskpart
list disk
select disk 2
(select 1863GB disk)​
list partition
select partition 1
(select 1863GB partition)​
shrink desired=500
create partition primary size=500
format fs=ntfs quick
assign letter=H
active
exit
bcdboot G:\windows /s H:

After that boot into BIOS and change boot priority to boot from 2TB drive.
 

DragonGunner

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Apr 4, 2014
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Ok. This is, how you fix it. Execute from elevated command prompt. Regular command prompt will give error on last step.
If you get any errors, then stop immediately.

diskpart
list disk
select disk 2
(select 1863GB disk)​
list partition
select partition 1
(select 1863GB partition)​
shrink desired=500
create partition primary size=500
format fs=ntfs quick
assign letter=H
active
exit
bcdboot G:\windows /s H:

After that boot into BIOS and change boot priority to boot from 2TB drive.
Everything went fine until "active" where it spouted "the selected disk is not a fixed MBR disk. The active command can only be used on fixed MBR disks."
 
Hmm. You have partitioned the new drive in GPT. Old drive was MBR.

Ok, then. Not a big problem. Slight alterations to script are necessary

Execute from elevated command prompt.
Again - if you get any errors, then stop immediately.
diskpart
list disk
select disk 2
(select 1863GB disk)​
list partition
select partition 1
(select 1863GB partition, partition number can be 1 or 2)​
shrink desired=500
create partition efi size=500
format fs=fat32 quick
assign letter=H
exit
bcdboot G:\windows /s H:

After that boot into BIOS, set boot mode to UEFI and change boot priority to boot from Windows Boot Manager (2TB drive).
 
Run chkdsk on G: drive
chkdsk /f G:

If that doesn't fix RAW file system, then you'll have to reinstall or perform cloning.
Before install or cloning clean disk 2 with diskpart.
diskpart
list disk
select disk 2
clean

Disconnect all other drives if you decide to reinstall. Leave only one drive connected.
 
Last edited:
Solution

DragonGunner

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Apr 4, 2014
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Well I disconnected everything, cloned from the old SSD, reconnected, set the boot order, and everything's fine again. Thank you all for all your help and I hope this doesn't happen again!
Have a happy holidays <3

PS If anyone has any ideas about why the clone worked but reinstall didn't, or what I might have done to have cause this in the first place, PLEASE let me know your thoughts.
 

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