“This file cannot be saved because some properties are missing or invalid. Use the Document Information Panel to provide the correct property values. Errors for required properties are marked with a red asterisk, and errors for invalid properties are marked with a red dashed border.”
I received this error, after updating content pages in SharePoint. After filling all the columns with data and removing the requirements, still no go. I could add an item, but not edit one, but was able to put the columns into quick edit and update.
The error was corrected by removing all of my hidden columns in the content pages and adding them back in.