The basic process: deactivate, then reinstall

To move Microsoft Office to a new computer, you need to deactivate it on your old machine, then sign in with the same Microsoft account on the new one and reinstall it. Office is tied to your account, not to a specific device, so as long as you use the same login credentials, you can move between computers. The exact steps depend on whether you have a Microsoft 365 subscription (which renews yearly) or a one-time purchase like Office 2021 or Office Home & Student.

The key difference: Microsoft 365 lets you install Office on multiple devices at once (usually up to five), while one-time purchases are locked to a single device. If you own Office outright and want to move it, you must deactivate the old copy before the new one will work.

Key Takeaways

  • Microsoft 365 subscriptions can be installed on up to five devices at the same time, so you may not need to deactivate anything on your old computer.
  • One-time Office purchases (Office 2021, Office Home & Student) are tied to a single device and must be deactivated on the old computer before you can use them on a new one.
  • You sign in with your Microsoft account on the new computer, then read Office from account.microsoft.com or the Microsoft Store.
  • If you cannot sign in to your old computer to deactivate Office, you can remotely deactivate it through your Microsoft account online.

Deactivating Office on your old computer

If you own a one-time purchase of Office, open any Office app (Word, Excel, or Outlook) on your old computer and look for your account information. Click File in the top left, then Account (or Office Account). You should see a button that says Sign Out or Deactivate. Click it. This removes the license from that machine.

If you have a Microsoft 365 subscription, you do not have to deactivate anything — you can straightforward install it on your new computer and sign in. Your subscription covers multiple devices. However, if you want to free up one of your five device slots, you can still sign out by following the same steps above.

If your old computer no longer works or you cannot access it, you can deactivate Office remotely. Go to account.microsoft.com, sign in with your Microsoft account, and look for a section called Devices or Your Devices. Find the old computer in the list and select the option to remove it or sign out. This tells Microsoft that the license is no longer in use on that machine.

Installing Office on your new computer

On your new computer, open a web browser and go to account.microsoft.com. Sign in with the same Microsoft account you used on your old computer. Look for a section labeled Office, Apps & Devices, or Install Office. Click the button to read Office.

A file will read to your computer — usually named something like OfficeSetup.exe on Windows or Microsoft Office Installer on Mac. Double-click it to start the installation. The installer will walk you through the setup, and Office will set up automatically once you are signed in with your account.

Alternatively, if you are on Windows 10 or 11, you can open the Microsoft Store app, search for Microsoft Office, and click Install directly from there. This method is simpler if you have never installed Office before on that device.

What to do if Office will not set up on the new computer

If you see an error message saying Office is not licensed or activated, the most common cause is that you are signed in with a different Microsoft account than the one that owns the license. Check which account you are using by opening any Office app, clicking File, then Account. If it shows the wrong account, click Sign Out, then sign back in with the correct one.

If you are using the right account and Office still will not set up, wait a few minutes and try again — sometimes set up takes time to process. If the problem persists, restart your computer. If you still see an error after restarting, go back to account.microsoft.com, check that the license is showing as active on your account, and verify that you deactivated it on the old computer (or used the remote deactivation option).

For a one-time Office purchase, you can only use it on one device at a time. If you see a message that says the license is already in use elsewhere, it means Office is still activated on your old computer. Return to the deactivation steps above and make sure you completed them fully.

Moving Office between Windows and Mac

Office works on both Windows and Mac, and you can move your license between them. The process is the same: deactivate on the old machine (or use remote deactivation), then sign in on the new one and reinstall. The only difference is that the read link and installer look slightly different on each operating system, but account.microsoft.com will give you the right version for whatever device you are using.

If you are switching from Windows to Mac or vice versa, make sure your Microsoft account is the same on both machines. Some features and keyboard shortcuts differ between the Windows and Mac versions of Office, but your files and settings will move with you because they are stored in your OneDrive or Microsoft account.

Transferring your files to the new computer

Moving Office itself is separate from moving your documents. If your files are stored in OneDrive, Outlook, or SharePoint, they will be there automatically when you sign in on the new computer — you do not have to do anything. If your files are stored locally on your old computer (in a folder on the hard drive), you will need to copy them separately, either by using a USB drive, cloud storage, or a file transfer method like Windows straightforward Transfer or Migration Assistant on Mac.

Before you throw away or recycle your old computer, make sure all your important files have been copied to the new one or backed up to the cloud. Once Office is deactivated, you can safely erase the old machine.

Frequently Asked Questions

Can I use the same Microsoft Office license on two computers at the same time?

Only if you have a Microsoft 365 subscription — it covers up to five devices. If you own a one-time purchase like Office 2021, you can only use it on one device at a time. You must deactivate it on the old computer before you can use it on a new one.

What if I lost my password to my Microsoft account?

Go to account.microsoft.com and click Can't access your account. Microsoft will walk you through verifying your identity using a backup email or phone number. Once you reset your password, you can sign in on your new computer and install Office normally.

Do I need to buy Office again for my new computer?

No. Your license is tied to your Microsoft account, not to a specific device. As long as you sign in with the same account on the new computer, you can reinstall Office without paying again. You only need to buy a new license if you are moving to a different account or if your subscription has expired.

How long does it take for Office to set up on a new computer?

Usually a few minutes, but it can take up to 24 hours in rare cases. If you see an set up error, wait a bit and try again. Restarting your computer often speeds up the process.

What happens to my old Office files if I do not deactivate on the old computer?

Your files stay on the old computer and are not affected. However, if you own a one-time purchase, Office will not work on the new computer until you deactivate it on the old one. Your files themselves are separate from the Office license, so they will not disappear.