I have had my first back up running for 12 hrs on my new MacBook Air. It wants to back up 36Gb of data. In the last 4 hrs it has only backed up 3GB. It is only 1/3 of the way done. Is this normal? I have everything Wi-Fi off in the house except the MacBook Air and time capsule, so it should be running at "N" speed. And it is in the same room at the Time Capsule. Is something wrong causing it to run so slow? I am very new to mac.