Actually this is exactly what I do every day. Aperture asks for my license everytime my macbook pro boots up each day. If I leave my machine running then I can open and close (after the first time I enter the serial numbers ) the program with no issues. I don't know if something is getting erased when I start the machine?
You may have a corrupted "ProAppSystemID" file or Aperture cannot write to the System Library.
To stop Aperture asking for the serial number, first check, if you still have an old file "ProAppSystemID" in your System Library.
- Quit Aperture.
- Go to your MacintoshHD and open the folder "Library", then "Application Support", then "ProApps".
- Remove the File "ProAppsSystemID" to the Desktop, if it exist and restart Aperture.
- Reenter your serial number, hopefully for the last time.
Sometimes Aperture writes this file to a temporary directory, when it cannot write to the Library. If the above does not work, look at the temporary directory /tmp
Use the Finder's "Go" menu
Go > Got to folder and enter /tmp into the textfield. If you see the file there, move it to its proper location.
Make sure, you are logged in from an Administrator account, when you enter the serial number, so that Aperture has the permissions to write to the system library.