I am a strong advocate of the manual labor in the IT industry: any convenient solution, i.e. “master” or a “wizard” would give you a lemon sooner or later.
TimeMachine backup would mess your user permissions in some cases, hard drive cloning would migrate your 2006 kernel extensions onto a 2017 Mac and VMWare or Parallels Migration assistant would drive you crazy even if you manage to complete the process successfully, transferring all the Windows flaws alongside your user data.
Nothing is better than a clean and maintained install.
However, sometimes we’re not speaking of reliability and just want a virtual machine for some transitional period. And the aforementioned third-party applications just fail to migrate your Windows from PC to a virtual machine (which happens both due to Windows issues and custom partitioning and hardware). So here’s a last resort measure that we all have thanks to Microsoft.
Note: this guide is for Windows 10, but would work for Windows 7 too, albeit modified slightly.
Proceed to press the ex-Start Button, then the cogwheel icon to access the Windows Settings panel.
Settings > Update and Security > Backup > Go to Backup and Restore (Windows 7)
Set up backup and proceed to save the image backup using the “Create a system image option” to an external NTFS-formatted drive ignoring all of the warnings. Disconnect the drive and plug it into the computer hosting your virtual machine.
Set up the new Windows 10 virtual machine using the official image from Microsoft, and forward the external drive with the backup of your pre-existing download to the virtual machine.
Boot into recovery
Troubleshoot > Advanced options > System image recovery > Use the latest available system image
This time you’d need to restore from a backup: “Select another back-up to restore files from”.
If the option is missing, consider expanding the panel to full-screen.
Select the “Select all files from this backup” option and proceed to restore these to their original location.
please take this with a grain of salt as this method requires a lot of time and is not guarantteed to work (i.e. Windows versions mismatch might occur failing the whole process). But as we all know, dedicated software sometimes fail and having another option of migration could be a lifesaver.