I would appreciate it if anyone can shed any light on this. After updating two old iMacs (2007, 2009) to Mavericks, each with 4GB RAM and more than 200 GB data onboard, they zipped through indexing in less than 2hours. After updating 2012 Macbook Air and late 2013 MacBook rPro, each with 8GB RAM and less than 70gb data onboard ... They both took 2weeks running day and night with the hard disk not sleeping! I spent ages on the phone with Apple Support, a level one guy, and did everything he suggested, but it made no difference. Any ideas?