Thank You for the images...That makes things so much clearer....
The problem is on your mac and not an office 365 customer
IF you were one of our customers, i would help you but I do not want to be responsible if you delete something and it messes up your programs or data.
You have two choices
1. Uninstall the entire office suite and data/cache and reinstall to see if it fixes it.
2. Troublesoot the issue
Both options need you to navigate to folders inside your ~/Library/ folder and any thing you do wrong in there can cost you.
You can check to see if you have a duplicate file of the normal.dotm located in Library>Application Support>Microsoft>Office>User Templates
Or google online for solutions to fix it
Good luck