File and Folder Updates

I just moved dozens of folders from my hard drive onto a new My Book external desktop storage device. When I look at the details for my folders, it showed the last time I actually updated them on my hard drive, which is good. However, I’ve since modified some of the folders, but the “Date Modified” field has remained the same, which is NOT good. It’s important that I am able to track the dates I add to or delete files in these folders. Has anyone else had this issue? If so, how to resolve?

If you are not using a My Cloud device, your question would be better served in the dedicated My Book subforum where people more knowledgeable about the My Book may be able to assist. The My Cloud is a different device than the My Book.