the project could not be loaded, it may be damaged or contain outdated elements

[katebrown.gold@gmail.com]

I am trying to create a new premiere pro project that combines 5 old projects. I made the projects a year ago, but have been updating them in the past week: they all run fine on the latest Premiere Pro 14.3.1 and have been saved with a new name. I have tried importing the projects into a new project, but I get the error message: "the project could not be loaded, it may be damaged or contain outdated elements"

Any way around this? 

How can I diagnose the problem if each of the 5 individual projects open fine?

Thank you!

[Michael Grenadier]

what happens if you have the projects open separately and simply copy and paste the contents of each project into the new project?  I'd save the new project after each addition...