Bcdboot “Failure when initializing library system volume”

When you run the Bcdboot command to copy boot files to the EFI system partition, the following error may occur:

Failure when initializing library system volume.

The output contains the list of Bcdboot command-line arguments.

Cause

The above error occurs if you mention a non-existent drive letter in the Bcdboot command line.

For example, your command line may be “bcdboot c:\windows /s Y: /f UEFI“. If the Y: drive is not assigned to any partition, the error occurs.

Resolution

To resolve the issue, assign the drive letter for your EFI partition using one of the methods below.

Option 1: Use the Mountvol command

Open an admin Command Prompt and run:

mountvol Y: /s

The above command assigns the EFI partition drive letter Y. However, the drive letter assigned using this method is valid only for the current logon session and will be lost after a restart.

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Option 2: Use Diskpart

Launch the diskpart environment by running:

diskpart

Type:

list vol

Note the volume number of your EFI partition, which is always a FAT32 partition. Its size typically ranges from 100 MB to 500 MB, but there is no mandatory limit for the partition size.

select volume #

(replace # with the actual volume number of the EFI partition).

assign letter=Y

exit

That’s it. You have now assigned a drive letter for the EFI system partition, and the Bcdboot command should now work correctly.