My internet is having a intermittent connection causing for the usual update to stop so I downloaded the Yosemite update from an external source. I copied it to the Application folder and when I try to install it the error "Copy this application to a writable Mac OS extended formatted disk...". My Mac's harddrive is currently formatted to Mac OS Extended (Journaled). I also tried to copy the file in a flashdrive and also formatted it as Mac OS Extended (Journaled) but the error is still the same.