Here's how to retrieve your Office product key via Windows. Some versions of Microsoft Office can even be installed on more than one device.īut what about if the worst happens and you lose your product key? Does that mean you can't reinstall office again?įortunately, all is not lost. That crucial information is required when installing it on your machine, and means you can reinstall it at any time should something go wrong. If your device isn't one of the few to come with Microsoft Office pre-installed, it's highly likely you'll get a product key when purchasing the software.