A family of Microsoft word processing software products for creating web, email, and print documents.
Hi
I suggest repairing Office to address this Word startup error:
Save your work and close all Office applications.
Open Settings > Apps > Installed apps (Apps & features on Windows 10). Find Microsoft 365 or Microsoft Office, then select Modify.
Choose Online Repair > Repair. Keep your internet connected, then restart your computer once it finishes.
Microsoft’s repair instructions: https://support.microsoft.com/en-us/office/lifecycle/repair-an-office-application
If the error continues, please share a screenshot of the full message and confirm whether it affects every document or only one.