When using OotD, an error pops up that says: "Could not read the Calendar"

This is usually due to an issue with either your PST/OST file or with your Outlook Views. Try the following steps to resolve it:
  1. Press your Windows Key + R and then in the run dialog type: Outlook /cleanviews and press enter.
  2. If that didn't work, try following the instructions here to repair your OST/PST