Accidentally Deleted Win 10 From BCD

Ex_Brit · 14 Oct 2022

I was dual booting Win 10 Pro x64 with Win 11 Pro but W11 was too unstable
I booted back into 10 & formatted the 11 out of existence/
.
Before shutting down last night the last thing I did was delete W11 from the BCD (using EasyBCD).
In my tired state I must have accidentally deleted the W10 entry.
Today boot insistS on starting. NON-EXISTENT W11.
I have tried repairing with my W10 system disk to no avail,. But my knowledge of same is limited.
I have no knowledge of Command Prompt which might salvage my sanity.
I did determine that W10 was alive and well on partition G but I can’t repair it for some reason.
Short of a clean install is there anything I can do? Also can I return drive letter C to W10?

HELP !!

Am typing on my iPad which is all I can use to post here.

SIW2 · 14 Oct 2022

presumably you tried running startup repair from the installation media?
You could try adding the entry with bcdboot command.

We don't know your setup, but if there is only one system partition you can try this:

boot the installation media in the same mode as your win10 installation ( either efi or bios )
then go to command prompt and find the letter of the win10 partition :

diskpart
(then press enter)
lis vol
(then press enter)

make a note of your win10 drive letter

then exit diskpart by typing

exi
(then press enter)

then type bcdboot win10letter:\windows

so if your win10 letter is D as seen from the booted installation media

bcdboot d:\windows
(then press enter)

[if there is more than one system partition, you might need to specify it, which is slightly more complicated]

Ex_Brit · 14 Oct 2022

OK it is drive G: which is the letter the Win11 gave it, and the cmd was successful. Reboot & hope it works?

Ex_Brit · 14 Oct 2022

It worked! Thank you so much!
Very slow to startup but start up it did ;-)

Ex_Brit · 14 Oct 2022

I tried thanking you using that button, nothing happened.

SIW2 · 14 Oct 2022

Ex_Brit · 14 Oct 2022

SIW2 said:

presumably you tried running startup repair from the installation media?
You could try adding the entry with bcdboot command.

We don't know your setup, but if there is only one system partition you can try this:

boot the installation media in the same mode as your win10 installation ( either efi or bios )
then go to command prompt and find the letter of the win10 partition :

diskpart
(then press enter)
lis vol
(then press enter)

make a note of your win10 drive letter

then exit diskpart by typing

exi
(then press enter)

then type bcdboot win10letter:\windows

so if your win10 letter is D as seen from the booted installation media

bcdboot d:\windows
(then press enter)

[if there is more than one system partition, you might need to specify it, which is slightly more complicated]

👍👀💪