Hi Debasish Kar,
I understand how frustrating this can be, especially when DISM completes successfully and all expected Windows files appear to be present, yet BCDBoot immediately fails with "Failure when attempting to copy boot files". Based on the information you provided, I can see that DISM completed successfully and the deployed Windows files (including winload.efi) are present, but BCDBoot fails immediately with "Failure when attempting to copy boot files".
To narrow this down further, could you provide:
- The exact
bcdbootcommand you are running. - Whether Windows 11 is installed in UEFI or Legacy BIOS mode.
- Whether the VHDX contains only the Windows partition or also contains its own EFI System Partition.
In the meantime, please try the following:
1, Confirm the VHDX is attached and assigned a drive letter
Open Disk Management and verify that the Windows partition inside the VHDX is mounted and accessible (for example, V:).
2, Try specifying the firmware type explicitly
If your host system is UEFI, run: bcdboot V:\Windows /f UEFI
3, Check whether BCDBoot can access the system EFI partition
Assign a drive letter to the EFI System Partition temporarily:
mountvol S: /s
bcdboot V:\Windows /s S: /f UEFI
If BCDBoot succeeds when the EFI partition is specified explicitly, the issue may be related to locating the target boot partition automatically.
4, Verify the deployed image architecture matches the host
For example, ensure you're not deploying an x86 image onto an x64 UEFI boot environment.
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