Maverick installation problem Trying to install OS X Mavericks the computer re- started as part of the installation process but when it came back on it just has a white square half way down with the x in a circle and above says download OS X. There is no desktop or launch pad behind so I can't do anything at all! What can I do?
Turn off the Machine by holding the power-button.
Start again while holding the alt-key, there should be a recovery-partition that lets you reinstall