"Date Modified" – Folders

MS1234 wrote:

Thanks Luis.

I take it, then, that neither the folder nor the subfolder can be made to show that they have changed, when their contents are altered, and there's nothing I can do about it.

I hope Apple will note this problem and do something about it.

I can understand your point of view. But let me try to explain why Apple will not "do something about it".

In a sense, even if you have a hierarchy of folders A/B/C/D/E and add a new file to E "now", you could defend that something deep inside A has changed, so the date must change; in that interpretation, you would have all the modified dates for A, B, C, D, E to be changed to "now". But also, in a way, that could be perplexing. Imagine looking at A suddenly have a new date when you look at it and it has the exact same files as before.

Philosophical things aside, the fact is a folder - called a "directory" in Unix terms - is in reality just a special kind of file, that lists the contents thereof. So the contents of A would be the things that sit directly inside A, like B and possibly other files. By changing E, nothing physically changes in A: the file A (again, a directory is just a file with special "flag", and a list of contents) did NOT, in effect, change, at all.

This is something that is working in a very definite way, has worked like this ever since Unix began to exist in the late 1970s. It is not a bug, it is working as intended - even if it does not match the expectations of some users.

Folder is a poor term to use, in that when you think of a physical manilla folder, the physical document is actually contained in the manilla folder.

Directory is actually a better term, as a physical directory is just a list of names and pointers to where you can find the item. A directory in the lovy of a building Associates nanes with office locations. A physical phone book Associates names with phone numbers. Or your contacts list, where the people do not live in your list, but it has information so you can contact them. And more than one contact list can have that person in it, even with a different name (Mom for you and Mrs MS1234 in a different list). And most people do not know which contact lists have their contact information.

A file system directory (aka folder to the Finder) is just names and location pointers to where the file can be found. The file exists outside of the directory. And multiple directories can point to the same file.

And a file does not know what directories are pointing at it. So if you modify the contents of a file, the file does not know what directory (or directories) are pointing at the file, so it cannot tell macOS what parent directories would need to have dates modified.

As Luis said, a directory is just another file, and its modify date only gets changed if you add, remove, or rename a file in the directory.

NOTE: the physical file does not have a name on it. The name ONLY exists in the directory. And if 2 or more directories point to the same file, each directory can have a different name for the same file.

Did you try a Finder search? There is so much power there. You can combine as many criteria as you want to find stuff. Date, size, file kind, name, contents, image dimensions or format... in any Boolean combination you can think of. It is in my opinion one awesome and underused feature. Oh, and you can save these search criteria as smart folders.

The Finder can do searches based on dates.

Narrow your search results on Mac - Apple Support

Say you have Folder/Subfolder

The Date Modified of Folder does not change if you added an item to Subfolder; only if you add something to Folder itself.