Losing Office Activation licenses on certain computers after upgrading Windows 7 to Windows 10

My Friend is a System administrator on our company, and he recently upgraded some systems to Windows 10 from Windows 7.

He had an issue where one of our systems lost its activation for Office Home & Business 2016.

This key was only installed on this computer. he tried to re-enter the key as well as reinstall using that key, but it says “that key has already been used”. So that system is currently stuck with an unlicensed version of Office, which is unusable. So far (knock on wood), the other computers have not lost their licenses yet and they are still activated.

However, we also have a network inventory program that scans all our computers. It usually gives us the Office key we used to install the office.

However, for these certain computers we just upgraded to Windows 10 (only about 9 so far), that inventory program is not showing the Office key for those computers anymore. T

his worries me. Luckily, there is only that one computer right now that lost it’s activation and would not let me re-enter the key. But he worried that it will eventually do this with the other computers, especially since the inventory program is no longer showing a key for the Office install on those systems.

Is there anything he supposed to do before these Windows 10 upgrades to assure that we do not lose our Office license/keys during the upgrades?

To prevent this from happening again, Is there a way he back-up a certain file and just restores it after the upgrade to Windows 10?

Some programs do this, but he is not sure how well they work.
Worst case scenario, can Microsoft reactivate the key for me over the phone? Or will it be a tedious process?

Is there a way to prevent this or restore the activation/license after the upgrade?

hello @Craftsman

When you first activated the software did you link the keys to a Microsoft account? That’s how its down now - you’d sign in with the Microsoft account to activate the software.