500GB Hard Drive with Windows 10 installed that works when installed in a Mac Pro. Doesn't work in a G4 or G5.

You may see this message: Windows isn’t activated, activate Windows now.
Don’t worry, this is a full functioning copy of Windows 10 Pro. It’s not necessary to activate this copy.

There are just two limitations that I have come across:

• Watermark on the lower right-hand corner saying Activate Windows.
• You cannot use anything under Personalization e.g. change wallpaper, accent colors, lock screen, themes, etc.

Other than this you have a fully-functional copy of Windows 10.