During playback of footage (not just HD, but some DV too), the playback suddenly stops and I get the 'Dropped Frame' dialogue window. I'm editing on a brand new imac and am pretty sure it should be able to playback DV footage and a freeze frame of that footage without that 'dropped frame' problem as soon as the freeze frame clip begins. So, all I can figure is that my my USB 2.0 500 GB WD external hard drive that's at only 50% capacity is just too old. I'm thinking an upgrade to a 1TB firewire 800 external hard drive would fix the problem, but this is mostly intuition. Any ideas on why I keep running into this dropped frame problem and if I'm on the right track re solution?