Can I upgrade directly from Mac OS X 10.5 Leopard to 10.7 Lion? [duplicate]
Solution 1:
According to this page, you need to get on Snow Leopard before installing Lion. It also gives hardware compatibility requirements, which are basically that you have an Intel Core 2 Duo (note: NOT Intel Core Duo), Core i3, Core i5, Core i7, or Xeon processor in your Mac.
Solution 2:
Please consider not only the technical but also the legal issues: Lion's license agreement requires that you own a valid license for Snow Leopard before installing Lion.
Check: https://www.macworld.com/article/161087/2011/07/install_lion_over_leopard.html for a detailed explanation of the methods availiabe to Upgrade from Leopard -> Lion