Namespace does not correspond to file location

I'm new to Rider and have really enjoyed using it over the last week.  However, when I opened my C# project this morning, I am getting warnings for all my classes and structs that state “Namespace does not correspond to file location”.  Nothing in my project has changed from yesterday when everything was warning free.  I see I can right click on each folder where my source files are, and clear the “Namespace provider” checkbox which resolves the problem for the files in that directory.  My question is why would this start nearly a week into the project when everything was working fine 24 hours ago?  No software or plugin updates have happened in the last 24 hours.