during the Win10 Education installation process I create a 100GB fixed size VHDX (1) and a second VHDX (2) with the fixed sized VHDX as its parent. After attaching the fixed size VHDX (1) I successfully installed Win10. After installation I created a second boot entry with BCDEDIT (copy {current}) and set the "child" VHDX (2) as the new device to boot. I did the same procedure with Win7 a few years ago and it worked perfectly fine (with VHD instead of VHDX). But when I try to reboot and select the new boot entry with the "child" VHDX I get an error message "VHD_BOOT_INITIALIZATION_FAILED".
I searched on the internet but I couldn't find a solution. Yes, there is enough free space at the hard disk to expand the "child" VHDX during boot process and it worked with Win7 exactly that way.
What am I doing wrong? Is there no support for booting expandable VHDX?
Thx for your help.