Thickness is not defined for one or more shells

Hi - I keep getting this error when I right click on my static study.  But...  all of my shells have a thickness.  How do I eliminate this error?

Similarly, I keep getting an error that the model may have updated.  But...  the model hasn't changed, and I've already clicked "Update All Components" multiple times.

Thank you!

Jon

SolidworksSimulation