Launch the Terminal App (located in /Applications/Utilities) and type this command:

  • Replace YYYY with the year,
  • MM with the month,
  • DD with the day,
  • hh with the hour (0 through 24),
  • mm with the minutes, and
  • ss with the seconds of your desired creation date.

Before pressing Return, insert a space and then drag-and-drop the file you want to change into the Terminal window. Then press Return, and you have just changed the creation date of your desired file.

If you’d like to change the modification date, start your line with touch –mt instead of touch –t.