Follow the steps.

1. Run Office Updates. From any Office app that will open go to Help > Check for Updates.
2. Repair Permissions on your Primary Drive… to do this execute the Disk Utility.app program located in Applications/Utilities.
3. Restart your computer
4. Before starting any Office applications run Font Book.app, which is located in your Applications directory. Use its Help function to guide you through… From the Edit menu run the “Look for Enabled Duplicates” function. With Yosemite all duplicates MUST be deleted. Then after selecting All Fonts from the File menu run Validate Fonts and resolve any remaining issues.
5. Power down your computer, which means shutting it down completely.
6. Power up the computer, which forces a reloading of fonts and then test Office