Before downloading, ensure your Mac meets these minimum specifications:
Already running OS X Snow Leopard 10.6.6 or later (10.6.8 recommended). Memory: At least 2GB of RAM . Storage: At least 7GB of available space . How to Install Mac OS X Lion 10.7.5 Free Download
You can download the official DMG installer directly from the Apple Support Download Page . Before downloading, ensure your Mac meets these minimum
This installer is with any Mac that originally shipped with Mac OS X Mountain Lion (10.8) or later. If your Mac is running a very old version like Tiger (10.4) or Leopard (10.5), you must first upgrade to Snow Leopard (10.6) before you can install Lion. Mac OS X Lion 10.7.5 Free Download
Open the "Install Mac OS X Lion" app from your Applications folder and follow the on-screen instructions. Important Compatibility Note