Microsoft also indicates that there will be a few cases where users will not be able to re-activate Windows 10 at all.

Using the Windows 10 Activation Troubleshooter will only work on Windows 10 Home and Windows 10 Pro editions, and there will be a limited number of times that you can re-activate your digital license although Microsoft does not indicate the maximum number of times. If Windows 10 users already use their MSA to log into their activated Windows 10 Home or Pro device, their MSA will be automatically connected to the Windows 10 digital license.Using the Windows Refresh Tool to clean install Windows 10 will not help your device Sarkar and her Microsoft team decided that after looking at Windows Insider feedback, they would allow users to link their Windows 10 activation digital license to their Microsoft account (MSA). “For example – if your device has a digital license (formerly called “digital entitlement”) for Windows 10 Pro from a previously installed activated Windows 10 build but you accidentally re-installed Windows 10 Home on such a device, the troubleshooter will automatically guide you through upgrading to Windows 10 Pro and activate Windows.” Sarkar found that in some installations, users would have trouble using Windows 10 on their devices: The Activation Troubleshooter will be available officially as part of the Windows 10 Anniversary Update coming next month and is currently available for Windows Insiders with the new Preview build 14371.

Windows 10 activation repair tool