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I’m getting ready to sell my MacBook Pro (Early 2011) and want to erase the hard drive and do a fresh install of Yosemite. I’m currently running 10.8.5 Mountain Lion. I bought the computer used, and do not have the original install disk (should have been Snow Leopard). The hard drive is currently formatted as MBR, and disk utility won’t allow me to access any erase options, create new partitions or select the GUID scheme. I’m also unable to access internet recovery mode when booting with cmd + option + R. Any ideas on how to at least clear the disk? Even better if I can get it to GUID so that I can install Yosemite. Thanks!
Do you have access to a second Mac? If you do you could try connecting your system to it via FireWire and startup your system in Target mode. At that point your system acts like an external drive. Using the other system will allow you to delete the partition and setup & install a fresh OS install. Update » 8/24/15 OK, While that will allow you to delete the partitions and reformat the drive it won’t work for an OS. Lets try this way: Get a USB thumb drive (16GB or larger)Download the OS installer from the App Store, make a backup copyThen create the GUID partition map on the thumb drive and format the partition with Mac OS Extended (Journaled) with Disk Utility.Run the OS installer and install the OS onto the thumb drive. Once done, copy to it the copy of the OS installer.Restart your system holding down the Option key so you gain access to the boot manager select the thumb drive.At this point you should be able to reformat the drive using Disk Utility on the thumb drive and using the OS installer on the thumb drive install a fresh copy of the OS. Do make sure you are connected to the internet as there are some updates your system will need.
