When files appear in one program but not another

I just answered this Super User question. Its poster was baffled as to why a folder structure created in a certain program was accessible to that program but not even visible in Explorer.

There's a Windows feature in play, specifically file system redirection. It was invented in the XP to Vista transition, where many programs still assumed they were running as admin and so tried to write to system locations. The feature makes the programs think the writing succeeded, but Windows actually stores the data in %LOCALAPPDATA%\VirtualStore, a per-user location. When the unaware program comes looking for the files, Windows adds any entries from the virtual store to the directory listing.

Since Explorer and other Windows utilities (like the command prompt) are in the know, they won't see the virtual files. That can lead to much confusion. Windows Vista's Explorer had a button to go to the virtual store, but that Explorer feature seems to have been removed.