After an upgrade to Mavericks and finally getting my system to something that resembled how I liked it before I went ahead and plugged in my Time Machine HD to back up and was greeted with the following 2 error messages:- 1) The system extension "/System/Library/Extensions/IOStorageFamily.kext" was installed improperly and cannot be used. Please try reinstalling it, or contact the product’s vendor for an update. 2) The system extension “/System/Library/Extensions/IOSCSIArchitectureModelFamily.kext” was installed improperly and cannot be used. Please try reinstalling it, or contact the product’s vendor for an update. I have reinstalled again OSX from recovery with no luck, tried the HD in another Mac and works fine, also tired another External HD and USB stick in my MBP to no such luck, does any one know how to solve this?* Please?? Thanks in advance. S. EDIT* - Simple repair disk permissions fixed this for any one with the same issue. Should have thought of this to be honest.