Hello,
Thank you for coming to the forum.
Does this happen when you open word, or when you open a particular file?
If it is when you open word, do a reboot of your device and try again and if it still does this, then repair the office installation on your device.
Repair office
- Right Click on Start > Select Installed Apps or Apps and Features
- Scroll down until you see Microsoft 365 Apps (or your office version)
- Click the three buttons beside the Microsoft 365 Apps (or your office version)
- Select Modify
- Click Online Repair (this will take a while to be done)
- Restart the device
Click the (reference) link below for guidance
https://support.office.com/article/7821d4b6-7c1d-4205-aa0e-a6b40c5bb88b
If it is a particular file, do the above repair on the office installation, then if the file still fails click the link to see if you can fix the file with the aids in the steps: https://support.office.com/article/47df9d48-2165-4411-a699-1786ac734bc3
Give feedback
Best Regards
Fuad