![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(76.8, 5%, 17%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3ERR%3C/text%3E%3C/svg%3E)
Microsoft 365 and Office | Install, redeem, activate | Other | MacOS
Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
When you activate a Microsoft Office licence, that becomes associated to the Microsoft account used as a digital licence, and after that, the product key can no longer be used to install/activate Office.
Do you still have access to the old device that Office was installed on?
If so:
1
If that is an Apple mac computer, open Word.
Click About Microsoft Word on the top menu, then on the resulting dialog box, in the 'Belongs To' section, you should see the Email address of your Microsoft account.
2
If that was a Windows PC, open Word.
Go to File - Account and you will see the Email address of your Microsoft account.