I updated my mavericks to beta version of yosemite. I formatted my PC by erasing all data from disk utility (cmd - R from boot up) and tried to re-install OS X to install beta 4 version. But I get the message mentioned in the title and could not install an OS on my machine. I am downloading mavericks app from the app store from a different machine to install mavericks again. Will I be able to downgrade to 10.9 ?