I've recently been encountering problems with my USB keyboard and also thunderbolt ports via my 2011 imac. First off I run a goflex thunderbolt adapter with an SSD as my system drive connected to one of the imac's thunderbolt ports, all of sudden last week on startup my imac does't seem to be able to see the SSD connected to it. It will take a few attempts of disconnecting and reconnecting before the SSD is visible as a boot drive. As roughly at the sametime, I've been encountering USB keyboard problems. To start with I thought my keyboard had just defect keys eg the backspace key stopped working and also the enter/return key. So i then tried an apple extended USB keyboard which I know works and for some reason the enter/return key does;t work on that either connected to the imac. I've done a few p r resets which have't seemed to solved any of the issues, I've booted into a clean install via my internal 1tb drive and still I have the keyboard issues on x2 different keyboards. I was getting a few kernal panics when the SSD via the goflex thunderbolt adapter when to sleep and woke up last week. Could anyone give me any help on this? could it be the logic board on its way out?