there is a lot of tools in the market can help in converting VMware VMs to Hyper-v , however one of the best tools that I always recommend is Disk2VHD , and recently it has been refreshed to support VHDX as well.
however when you start creating VHDX from a VMware machine , and you mount the VM in Hyper-v you except that it will work , unfortunately you will get a Blue Screen of death (BSOD) and 0x0000007B – “Inaccessible Boot Device” error. This is due to the fact the converted VM will have no Primary IDE Channel since VMware recommend by default SCSI Disk and Hyper-V will presume that the converted disk is IDE type and located on the Primary IDE Channel.
There are two workaround to fix this issue :
1- First Solution : Repair the installation and hope that it will not affect the Software installed (I don’t recommend)
2- Second Solution:
a. For each VMware VM , add a new IDE disk drive (any size will do let’s say 5 GB), Make sure that you select “Adapter: IDE 0 Device: 0” under “Virtual Device Node” while creating the new disk (otherwise we might end up with yet another SCSI disk.
b. Boot up the VM with both drives connected and check that it detects the new IDE drive (along with a primary IDE channel and a disk device driver). You should be able to see the new drive as "not initialized" in Disk Management.
c. Now the VM has the IDE Disk
D. start running your DISK2VHD