Mark tried downloading OS X Mountain Lion on his Mac Pro tower, but got an error and couldn't get it to work. He downloaded it fine on his Macbook Pro though, and wants to use that to install it on his Mac Pro. First he should make sure the Mac Pro is compatible with the upgrade. If it is, he can continue the process.
- Download Mountain Lion from the App Store.
- Ctrl + Click, or right-click on the installer and choose "Examine Package Contents".
- Open the "Resources" folder.
- Copy the "installESD.dmg" file to a USB key or DVD.
- Insert USB key or DVD into the system he wants to upgrade.
- Double-Click the file to install Mountain Lion.
It's a large file so this could take awhile. Once it downloads, it will automatically initiate the install. He should not install it though because once it installs, it will erase the installer.
He can make it bootable using a program called Lion Disk Maker that will create a bootable DVD, but Leo doesn't think doing this is all that necessary in this case.