Instructions on checking an MD5 checksum on a Mac OS X:

1. In Finder, browse to /Applications/Utilities.
2. Double-click on the Terminal icon. A Terminal window will appear.
3. In the Terminal window, type: “md5 ” (md5 followed by a space).
4. Drag the downloaded file from the Finder into the Terminal window.
5. Click in the Terminal window, press the Return key, and compare the checksum displayed to the screen to the one you have.