Each time that you create a new file on your Apple computer, the Mac OS X operating system automatically adds a tag to the file with the exact date and time it was created. This information is known as the file's creation date and can be viewed in the Finder application. If you want to change the creation date that appears for a certain file in the Finder, you can use a terminal command to set it to the date of your choice.
Click on the "Finder" icon in the dock at the bottom of the screen.
Navigate to the location of the file for which you want to change the creation date.
Launch the Terminal application, which can be found in the "Utilities" folder within the "Applications" directory.
Type "touch --t YYYYMMDDhhmm.ss" into the blank command prompt window and place an extra space at the end of the command text. Then replace "YYYY" with the four-digit year you want to use, "MM" with the month, "DD" with the date, "hh" with the hours, "mm" with the minutes and "ss" with the seconds.
Click on the file in the Finder and drag it into the Terminal window. When the file's icon is on top of the Terminal window, release your mouse button to automatically add the file's name and path to the command text.
Press the "return" key on your keyboard to run the command. The system will now change the selected file's creation date in the Finder using the information you have entered.
This process may not work on files whose names include spaces.