Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Uninstall Microsoft Office LTSC Professional Plus 2021, restart Windows, and then install Microsoft 365 using the account associated with your subscription.
1. Remove Office LTSC 2021
- Close Word, Excel, Outlook, and all other Office applications.
- Press the Windows key, type Control Panel, and open it.
- Select Programs > Programs and Features.
- Select Microsoft Office LTSC Professional Plus 2021.
- Select Uninstall and complete the prompts. Office suites normally must be removed as a complete package rather than one application at a time.^1^
- Restart the computer.
Do not delete the Office program folders manually; that can leave installation records behind.
2. If Microsoft 365 still detects Office 2021
Use Microsoft’s uninstall troubleshooter to remove leftover Office components:
- Open the Microsoft Support uninstall page cited below.
- Under Uninstall Microsoft 365, select the button that starts the uninstall troubleshooter.
- If prompted that the site is trying to open Get Help, select Open.
- Choose Office 2021 or the detected Office installation and follow the prompts.
- Restart the computer when requested.
Run the troubleshooter on the affected computer. It requires Windows 10 or later and supports removing Office 2021.^2^
This cleanup step is particularly relevant when Office no longer appears under Programs and Features, but the Microsoft 365 installer still reports that Office 2021 is installed.^3^
3. Install and activate Microsoft 365
- Go to https://m365.cloud.microsoft/apps.
- Sign in with the Microsoft account—or work/school account—associated with the new subscription.
- Select Install apps.
- Select Install or Microsoft 365 apps, depending on the account type.
- Run the downloaded installer and approve the Windows permission prompt.
- Wait for “You’re all set! Office is installed now”, then select Close.
- Open Word from the Start menu, accept the license agreement if prompted, and sign in with the subscription account to activate Microsoft 365.^4^
If Project or Visio is installed separately, do not remove it unless the Microsoft 365 installer specifically identifies it as another conflicting Office product.
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