FIX: "Unknown Error" or "Unexpected Error" in Microsoft Teams

If you're one of the many users that are experienced the "unexpected error" or "unknown error" while in Microsoft Teams (usually when clicking on the Files tab), then try one of the methods outlined in the video to resolve this issue.
1. Try opening in SharePoint
2. Log out, exit the application, restart your computer. Now try again.
3. End problematic tasks through Task Manager. Relaunch and try again.
4. Run Office Repair in "Apps & features"