Unity newbie (PC version and Visual Studio 2017). My existing project was saved with 2017.3.0f3. Opening the project with 2017.3.1f1 displays a window (Screen Shot). Clicking the Continue button opens the project in 2017.3.1f1. The window suggestion was: This may require re-import. How do I re-import or fix the problem?
I did find the answer, but it just took me more time! After starting the project, Assets > Reimport ALL did the fix. So sorry, but now I need to find how to mark as solved.