Last accessed date indicates when a file was accessed the last time. This attribute differs from modified date. While modification date indicates the last changes in file contents, the last accessed date does not necessarily presuppose changes of content. When a file is modified, modification and last accessed date is set to the same value. However if the file is only opened for viewing, copied, moved, or in other words - if file or folder is used in any way, last accessed date is changed to current one.
Like all file attributes, last accessed date is recorded in file system, not in the file contents. This file property does not interfere with the date stamps that are stored in the file itself. Various applications put their own date and time records in the file contents or meta-tags like Microsoft Office products.
Any viewing, copying or moving of the documents, images and other files automatically alters last accessed date stamp of the file.
C:\>fsutil behavior set disablelastaccess 0
Reference:
http://www.febooti.com/products/filetweak/online-help/file-last-accessed-date.html