If you intend to install the Mac OS X Yosemite public beta (10.10), please note that Parallels Desktop 8 for Mac will NOT run on the OS X Yosemite public beta. If you do install the beta, you will not be able to launch your Windows applications or directly access your files though Parallels Desktop 8. The Parallels Team is currently supporting Yosemite only on our current version, Parallels Desktop 9, and has not made any Yosemite-related updates to Parallels Desktop 8 at this time. If you do intend to install the Yosemite public beta for testing, your virtual machines and Windows apps will only run on Parallels Desktop 9 at this time. On the current beta version, Apple has suggested making a complete backup of your system prior to installing the latest beta.