The following installation guide describes how to properly install Ygopro on Mac OS X. Click on the images to view a bigger version.
OS X 10.8 or higher.
First download the dmg installer from the download page. Open the dmg by double clicking on it. Mac will mount a disk to your system that is labeled "Install Ygopro Percy".
A small window with 2 icons appears. Drag the icon that says "Ygopro" into the "Applications" icon.
Note: do not start Ygopro directly at this step! The dmg file is read-only. You will not be able to save decks and settings this way.
The installer will now copy the necessary files. This might take a few minutes.
After completing the installation you can eject the image.
To start the game click on "Applications" in the dock, then on "Ygopro". This will open a new page because Ygopro is installed into a folder.
Click on the Ygopro duel disk icon to start.