Maximum number of devices notification after Windows 10 upgrade

Q. I upgraded to Windows 10 and now I'm receiving a notification that I have exceeded the maximum number of devices and I need to deactivate a device but I have less than 10, what do I do?

A. This is likely because over time you have added devices and never removed them from your account. To resolve go to https://account.microsoft.com/ and select Devices. You will see all the devices associated to your account and can remove those devices that you no longer use.