Sunny day, all was well; -- until --, I changed some setting that only affects the C: drive. I checked the Folder Format tool; however, can not identify any values for C: drive that are different than for the other drives.
A bit embarrising that I can not figure this problem out. Thank you'all for your patience and support.
You haven't actually navigated into that folder, you've just expanded sub-folders to show their contents.
Single-clicking a folder in the tree (panel on the left) navigates, but clicking a folder in the file display (panel on the right) normally just selects it for file operations.
(Double-clicking a folder in the file display will normally navigate to that folder).