Hi Stuart. I'm Greg, 10 years awarded Windows MVP, specializing in Installation, Performance, Troubleshooting and Activation, here to help you.
Set a System Restore point first so you can go back if necessary. System Restore is your first line of defense if Windows ever malfunctions as it can run even from recovery media to get you back before a problem started like a time machine. It should always be turned on C drive with plenty of disk space (5-15%) configured. Here's how to check and when necessary how to run System Restore: How to Use Windows 11 System Restore Point (4 Ways)
Make sure you have all Windows Updates up to date in Settings > Update & Security > Windows Update > Check for Updates. Expedite them all including Optional Updates, including restart, go back and check again.
If the problem persists, Repair Office following this guide:
https://support.office.com/en-gb/article/repair...
If that doesn't fix it then reinstall Office as shown here:
https://support.office.com/en-us/article/downlo...
https://support.microsoft.com/en-us/office/down...
https://www.lifewire.com/install-microsoft-offi...
Feel free to ask back any questions. Please report back results for all steps given so I know what else to suggest if necessary.
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