I have encountered several times that, in Mac’s Finder application, the list of files and folders is not updated. For example, when i have drag a new file to the NAS storage server from a PC, the new file does not appear in Finder of another Mac. Maybe PC and Mac are not quite compatible to each other :p

At this moment, execute the following statement in the Terminal application:-
osascript -e ' tell application "Finder" to tell front window to update every item '