says "This disk does not contain the EFI system partition. If you want to use this disk to start the computer, or include it in the RAID disk array, back up the data on this disk partition."

http://support.apple.com/kb/TS3926

This didn't solve my problem

So what might your problem be?

Well, I'm trying to do first aid on my hard drive with disk utility, but when I do, it tells me "Alert: This disk doesn’t contain an EFI system partition. If you want to start up your computer with this disk or include it in a RAID set, back up your data and partition this disk."

The EFI partition is visible on disk utility for the first time and it's making me nervous.