Inventor (2020) not seeing step files

Well, this is new.  Never had a problem opening step files before.  Today, for reasons unknown, when I try to open a step file from within inventor, and I navigate to the folder the step file resides and…nothing.  Filetype is set to step, but Inventor just shows a completely empty folder, even though I am looking at that exact same folder in a file folder and the files are clearly there. 

I have tried restarting Inventor, but it made no difference.  The only way I can open a step file now is to right-click on the file itself in a file folder (outside of Inventor) and then select “open with” and then select Inventor.  Why Inventor suddenly doesn’t recognize step files is beyond me.  Even using “open with” is a pain, because it doesn’t list Inventor as one of the apps that will open it.  You need to go to “browse this computer” and then navigate to the inventor.exe file just to open the file.  Extremely cumbersome compared to opening the file from within Inventor. 

Has anyone else encountered this before?