I lost my main OS EasyBCD entry

P

palosanto

Member
I have a PC with win 8.1 which I was trying to wipe and install Win 10.
I wanted to install windows 10 from a partition of my 2nd HD to make it faster and, to be honest, to experiment with Easy BCD powerful features.

I copied the win 10 installation files from a CD to the new partition, made the partition active with Diskpart and made it bootable with EasyBCD so I had 2 entries in the Boot menu section of the program, the existing Win 8.1 and a second one with the Win 10 installation files.
But then (dont ask why) somehow I guess I deleted the Existing 8.1 entry!
So now when I try to boot only the win10 installation shows up and I still want to have windows 8.1 bootable so that I can get some files if I need them. Browsing with the command window when I'm repair mode of win 10 disk I can see that all my win 8.1 and documents etc are still there but of course all the drive letters are different, so at least I didn't loose anything in my main disk.
How can I fix that?
Thank for your patience with people (like myself) that shoudn't be messing with grown up toys,...

EDIT: I fixed it. Just booted with a CD and used bootrec commands to repair the MBR/
Thanks anyway
 
Last edited:
You could have just added an entry for W8.1 again
neosmart.net

Adding Entries

All operations regarding the addition of new entries to the EasyBCD menu and the BCD store can be performed from the “Add New Entry” page of EasyBCD (as selected from the “EasyBCD…
neosmart.net
The fact that drive letters were different is normal.
Drive letters are not "real", they don't physically exist on the hardware. They're a vitual labelling system used only by MS Windows and they're mapped in the registry of the running OS and assigned dynamically as Windows initiallizes, or by reference to user defined existing registry entries (assigned using Disk Management). They are therefore unique to each OS, so will differ from OS to OS unless you synchronize them yourself after installing a new OS.
There are no letters in the BCD, just a user-incomprehensible UID hashed from the unique device signature and the start position of the partition on that device.
EasyBCD translates that UID into a letter for you by reference to the aforementioned registry map, so when you need to add a new entry, you just use the letter the running OS (W10 for you) sees W8.1 as. It doesn't matter what W8.1 calls itself. The new W8.1 entry in the BCD will be constructed with the correct UID using W10's map and when you boot W8.1 again, EasyBCD will use its map to reconstruct that UID as whatever you were expecting (C presumably).
 
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