Yosemite 10.10 Install? So I'm trying to boot a yosemite installation from an 8GB USB with the dmg file I downloaded from the app store, but once I hit "option" during my mac's startup and choose the correct usb, I get the following error

"Cannot Install Yosemite on the Mac. Yosemite already has been installed"

This is of course false as I have OS X 10.7 and I'm trying to upgrade to 10.10

Any help or ideas?

Update: Per a suggest I've inputed the following code into my terminal:

pkgutil --packages | grep -i base ; uname -a ; sw_vers ; pkgutil --pkg-info  com.apple.pkg.BaseSystemBinaries


Here was the Result:

com.apple.pkg.BaseSystemBinaries
com.apple.pkg.BaseSystemResources
Darwin *****-*****-MacBook.local 11.4.2 Darwin Kernel Version 11.4.2: Thu Aug 23 16:26:45 PDT 2012; root:xnu-1699.32.7~1/RELEASE_I386 i386
ProductName:    Mac OS X
ProductVersion: 10.7.5
BuildVersion:   11G63
package-id: com.apple.pkg.BaseSystemBinaries
version: 10.7.0.1.1.1309412550
volume: /
location: /
install-time: 1436744136
groups: com.apple.snowleopard-repair-permissions.pkg-group com.apple.FindSystemFiles.pkg-group 


Hopefully this give more insight into my issue.

Thanks
Sounds like a fault, or that perhaps there is a conflict. You are trying to upgrade from 10.7 to 10.10 and its possible you either can't do that, or your machine is incompatible. Although I expect it would tell you as such.

In any case, what ever the reason is your only real way forward is to backup with Time Machine if you haven't already onto an external hard drive, and then do a fresh install rather than an upgrade.

After you've done this during the install process you'll be able to import old backups etc... You can use your backup from Time Machine to restore your files on OS X 10.10.