Eric's Ultimate Solitaire (also known as Eric's Ultimate Solitaire X) is a commercial solitaire game developed by Delta Tao Software for the Macintosh. The game was later ported to Linux by Loki Software.
Apple Computer bundled the game with some Macintosh systems.
As of January 4, 2012, Delta Tao Software had not released an update compatible with Apple's Mac OS 10.7 (Lion) operating system. As of November 21, 2013, Sniderware released Eric's All-in-1 Solitaire as its successor.