Currently Being ModeratedDec 11, 2012 2:51 PM (in response to Sidney Stetson)
I had a similar problem with a Lion iMac (stuck "preparing") that was eventually cured when Apple issued a system update. Have you run Software Update?
Currently Being ModeratedDec 12, 2012 12:02 PM (in response to Joe Sixpack)
Thanks, Joe. My software is up to date. I forgot to mention that, after this first began happening, I erased the external HD and had Time Machine start all over again. It did the first, complete backup overnight, but subsequent ones still take longer than they should and it still prepares 90,000 - 120,000 items when it should be doing no where near that many files on an hourly basis. I'm wondering whether the cable needs to be changed out, as well. We're running OS 10.6.8.