If you’re confused about what version of Office 365 you have and how many times you can use your account to log in on a device, check out Microsoft’s purchasing page if your account is listed on the screens shown in my above screenshots as an “Office 365 Personal” one, you’re only allowed to use it on one Mac or PC, but if it’s the more expensive “Office 365 Home,” you can install it on up to five machines. If you’re working with a PC or Mac that already has Office installed, you can simply sign in to activate the apps under your Office 365 subscription and restore full functionality. Speaking of activating Office 365, if you need to install the Office applications on a new PC or Mac, you can download the Office installer from the same page on which you deactivated your old device. The device you deactivated should now be missing from the list, which frees you up to activate your subscription on a new PC, Mac or tablet. Once you confirm the deactivation, you’ll be returned to your list of Office 365 installs. Microsoft will ask you to confirm the decision, and let you know that the Office applications themselves will still be present on the device (unless you manually uninstall them), but they’ll be limited to viewing and printing documents unless they’re activated with another Office 365 account or valid Office product key. Find the computer you’d like to deactivate and click its corresponding Deactivate Install link. This lists all of the devices on which your Office 365 account is currently activated (i.e., the PCs, Macs, and tablets on which you downloaded and installed the Office applications as part of your subscription). On the next page, scroll down a bit and you’ll see a section labeled Install Information. (Yeah, yeah, I know that’s not very intuitive.) Once you’re logged in, look for the button labeled Install Office and click it. To get started, log into your Office 365 account at Microsoft’s website.

How to activate office on mac