BCD on another disk

#1
Is it possible with EasyBCD to modify a BCD residing on another disk (without disturbing the BCD on the active disk) ?
I want to be sure before changing anything and eventually getting into trouble.

I cloned my Win10-partition to a SSD but can't boot into it because the (cloned) BCD on the SSD is still referring to the Win10-partition on the HDD.

Both HDD & SSD are MBR

Booting into the Win10-DVD for repair doesn't work: says cannot repair.

I use an non-Windows boot-manager which hides non active bootable partitions, meaning that the used bootable partition always is Drive C.
So the Win10 on the SSD will be Drive C when launched

I should find a way to modify the UID specified in the BCD.
 
Last edited:

Terry60

Knows where his towel is.
Staff member
#2
The disk letter given to the OS is set at installation time and recorded in the registry of the created system.
It's not influenced in any way by the boot manager.
You can boot multiple systems as C from the standard Windows bootmgr.
It doesn't matter that when you boot one, it refers to the other(s) as something other than C.
Disk letters are not "real". They only exist in the mind (registry map) of the running system and since it can only have one device for each letter in its map, it assigns other letters to every device and that includes partitions containing other OSs.
However, when they are booted, they have their own registry, hence their own map, so they will call themselves C and give the previously booted "C" some other letter.
None of those letters exists in the BCD, only displayed translations by EasyBCD of UID hashes into letters for your convenience.
In your situation, all that should be needed is to boot the Windows DVD to "repair startup" (three times)
I suspect that the 3rd party boot manager you're using is preventing the repair.
If you get rid of that, all you need to do to "hide" alternative OSs you don't want accessed, is to remove their disk letters using Disk Management.
Explorer doesn't display any drive without a letter, hence it can neither been seen nor accessed.

In answer to your opening question
EasyBCD > File > Select BCD Store will operate on any BCD you navigate to, but I don't know whether that will solve your problem.
You don't edit UIDs directly. EasyBCD does that through the aforementioned registry lookup. You just give it the appropriate disk letter and it finds the UID from the map.
Does your 3rd party manager even use the BCD ? It's an MS bootmgr file.
 
#3
All Windows installations are installed as drive C (at installation time all other bootable partitions are hidden).
That always worked fine.

Meaning the cloned partition is cloned as drive C too.
But .... when I boot the Cloned Windows partition on the SSD, after the Windows-startup logo it continues with the Original Windows partition on the HDD.

In Windows XP times that indicated a wrong disk/partition specification in the boot.ini : multi(0)disk(0)rdisk(0)partition(1)
Correcting that in the boot.ini solved the problem. So I'm assuming something like that is now stored in the BCD

My boot manager does not USE the BCD, it sets the selected instance as bootable and gives control to it and starts the normal boot-process on that partition. In this case Windows (and its bootmgr).
 

Terry60

Knows where his towel is.
Staff member
#4
What do the Disk Management flags say is "boot" when you try to boot the SSD ?

Disk Management flags have the following meanings

"boot" = "this is the system you're running"
"system" = "this is where I found the boot files for the currently running system"
"active" (on the first HDD in the BIOS boot sequence) = "this is where I started the search for the boot files"
"active" (on subsequent HDDs in the BIOS boot sequence) ="this is where I will look if I don't find something in the MBR on the first HDD"
 
#5
It's not the first time I use multiple OSes on one system. Actually I have 10 of them which are all perfectly booting.

The only question I have is, how is the equivalent of "boot.ini : multi(0)disk(0)rdisk(0)partition(1) " stored in the BCD, and how can I edit / modify it in any BCD.