Q: How do I find my serial number?

Click on the Aperture menu and choose About Aperture. Your serial number should be below your name in the Licensed To section.

I am in the same spot - aperture won't load without the serial number. I thought I had originally downloaded it directly about 4 years ago. I had to reformat my hard drive, and now it won't open so I can't get the serial number. Do I just need to buy the new version?

If you bought Aperture online, you should have received an email with the serial number - search your mail box. If you bought a boxed retail version the serial number is inside that box.

If you cannot find it, contact Apple; see this support article:

     Pro Application Replacement Serial Numbers: http://support.apple.com/kb/HT1861

Regards

Léonie