Hi, I'm currently trying to run an apple hardware test on a mid 2010 21.5" iMac running osX Mavericks as the iMac is running very slowly so I suspect a HDD failure is imminent.. Upon pressing (option + D) on start-up i'm greated by the image of a globe with it trying to connect and download. then being displayed with the error code -3403d. I have already searched the forums for this error and no one has gotten a reply, so I thought i'd start a new thread and get it to the top of list. I have made sure i am connected to my network, i am using an ethernet cable to do this. I can boot into recovery mode with (command + option + R). I have tried running first aid on both the HDD itself and the partition that MacOS is installed on. Any help would be greatly appreciated.