[fChk]

Interesting idea. I am also thinking about migrating my current Windows 10 installation to a VM disk.  But I am afraid I will need to re-activate my Windows 10 after the migration?

If you meant reactivation when reinstalling your Win10 on your physical machine again, then it's a simple formality done by reconnecting to M$'s servers. Your machine is supposed to have already been activated the first time you installed Win10.

On the other hand, if you meant inside the VM, then yes if your licence is of an OEM type, which is linked to your machine hardware. But if it's a retail licence then you have to reconnect to M$ server's to reactivate Win10 inside the VM.

For volume licensing, you have to reactivate it via the adhoc KMS server.

Damn it!... It's always complicated whenever you touch anything M$-ish related... What's more infuriating is that's done on purpose!..

And is there any easy way to do the reverse later if need? I mean the Virtual-to-Physical migration.

Of course there is!.. Would have been better if you opened a topic on this! But quickly, anyway:

Although hidden's method looks seems good/simple and the way to go for most of this forum's users, I'll nevertheless outline my way of doing things, for the more brave ones :-)

• Convert back your qcow2 (or whatever format you'll be using) into VHD with qemu-img.
  
• Then proceed the way you like or are most comfortable with:
  • If you still have a Win 6.x system in your boot (the way I have win7 still on), then you'll have to load that VHD into your filesystem and clone it into a physical partition and to make it bootable you'll have to fix its boot with the bcdedit tool.
    
  • The best way though is to not even bother with the cloning to physical stage altogether. JUST BOOT WITH THE VHD volume directly.
    

It's a little known secret among Windows average users that since Win7, people can boot their system directly from a bootable VHD volume (not from a physical partition.) I remember having posted a how to on this topic in the FFS forums back in 2014!.. I'll repost it here for this community in the coming days.