I made a partition for Yosemite. It's the only one I use. I want to delete the other one that came with my mac. It won't let me do it. How do I do it?

Question

Hello. I made a partition a while back for Yosemite. Now, I have two partitions. The Yosemite one and the other one that I made smaller and changed the name to Erase so that its easier. I need more space on my Yosemite one. How can I Make the Yosemite Partition have all of the memory. I hate that I know I have like 900 gigs lurking around my iMac that I can never use. Please help. Apple....somebody....

Answer 1

Erase the large partition. Clone the small volume to the large volume. Boot from the large volume. Delete the small volume then extend the large volume to the full size of the disk.
Drive Erase for Mavericks, Lion/Mountain Lion
1.  Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button. Select Disk Utility from the main menu and click on the Continue button.
2. After DU loads select the volume you wish to erase from the left side list. Click on the Erase tab in the DU main window.
3. Set the format type to Mac OS Extended (Journaled.) Click on the Erase button and wait until the process has completed.
Clone Yosemite, Mavericks, Lion/Mountain Lion using Restore Option of Disk Utility
Boot to the Recovery HD:
Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.
     1. Select the destination volume from the left side list.
     2. Click on the Restore tab in the DU main window.
     3. Select the destination volume from the left side list and drag it
         to the Destination entry field.
     4. Select the source volume from the left side list and drag it to
         the Source entry field.
     5. Double-check you got it right, then click on the Restore button.
Destination means the large volume. Source means the small volume.
When you finish select the Startup Disk from the Apple menu. Set the top volume as your startup volume. Click on the Restart button.