This question looks simple, but it becomes clearer once you separate redeeming the key from the actual install rights.<\/p>\n
For one-time Office purchases, the safest default is not ‘one key for two Macs.’ It is one computer, with the Microsoft account becoming the important part after the key has already been redeemed.<\/p>\n
Short answer<\/p>\n
For one-time Office purchases such as Office Home & Business, the safe default is one PC or Mac, not two Macs on one product key. Microsoft says these suites install on a single computer. If the key has already been redeemed, the normal reinstall path is the Microsoft account linked to that Office purchase. If you are moving Office to a different Mac, follow the transfer terms instead of treating it like a second install on another Mac.<\/p>\n