Subject to the terms of the End User Licensing Agreement, the primary user of the computer on which Photoshop Lightroom 2 (the "Software") is installed may install a second copy of the Software for his or her exclusive use on either a portable computer or a computer located at his or her home, provided that the Software on the portable or home computer is not used at the same time as the Software on the primary computer. You may be required to contact Adobe to make a second copy. Lightroom is sold as multiplatform software, which means it can be installed on either Mac OS X or Windows.