Hello,
I am looking for the best way to change the modified date of a folder to the newest modified of a file in that folder.
Example:
Master Directory Modified 5/18/2016 18:33
±->Folder_A Modified 5/18/2016 18:33
±–>Folder A.1 Modified 5/18/2016 18:33
File A.1.1 Modified 6/2/2013 01:00
File A.1.2 Modified 6/1/2013 01:23
±–>Folder A.2
File A.2.1 Modified 5/3/2015 05:33
±->Folder_B Modified 5/18/2016 18:33
±–>Folder B.1 Modified 5/18/2016 18:33
File B.1.1 Modified 12/31/2012 04:33
Both Folder_A and A.2 should have a Modified date of 5/3/2015 05:33 because that is the last modified file in that set of folders.
Both Folder_B and B.1 should have a Modified Date of 12/31/2012 04:33.
This is what I have, partly edited from a folder action.
on open
tell application "Finder"
set this_folder to (choose folder)
set folder_list to items of folder this_folder
repeat with new_file in folder_list
try
set latestFile to last item of (sort (get files of (this_folder)) by modification date) as alias
set modification date of this_folder to latestFile's modification date
end try
end repeat
end tell
end open
It works as a folder action, but it only changed the folder that I added a file to. It needs to run when doubt-clicked or when the folder is dropped on the app. Many sub folders too. Some of the information I see online is many years old and I’m not sure where to troubleshoot. I’m completely lost now. 
Hello again,
Is this not possible? Did I make a mistake posting here? I searched the site for a solution, but couldn’t find one. Is there a term for what I am trying to do that I might not be aware of, so I can continue searching elsewhere?
Thank you
Hi,
saved as an application this script works as applet and droplet and considers all subfolders
on run
set baseFolder to choose folder
processFolder(baseFolder)
end run
on open theItems
repeat with anItem in theItems
tell application "Finder" to set isFolder to class of anItem is folder
if isFolder then processFolder(contents of anItem)
end repeat
end open
on processFolder(aFolder)
tell application "Finder"
try
set latestFile to last item of (sort (get files of aFolder) by modification date)
set modification date of aFolder to latestFile's modification date
end try
set subfolders to folders of aFolder
repeat with subfolder in subfolders
my processFolder(contents of subfolder)
end repeat
end tell
end processFolder
Excellent! Thank you so much. I guess the processFolder and if isFolder is something I need to read up on. 
The script should find last modified item (that is, file or folder) of folders and subfolders in the entire contents of every processed folder inside the recursive process.
on run
set baseFolder to choose folder
processFolder(baseFolder)
end run
on open theItems
repeat with anItem in theItems
tell application "Finder" to set isFolder to class of anItem is folder
if isFolder then processFolder(contents of anItem)
end repeat
end open
on processFolder(aFolder)
tell application "Finder"
try
set latestFinderItem to last item of (sort (get items of entire contents of aFolder) by modification date) -- EDITED
set modification date of aFolder to latestFinderItem's modification date -- EDITED
end try
set subfolders to folders of aFolder
repeat with subfolder in subfolders
my processFolder(contents of subfolder)
end repeat
end tell
end processFolder