I was just having this problem and this thread is pretty old, but I unplugged my joypads and started it back up and it ran fine, plugged them back in, booted it up, froze again. I think its because I switched them from the back ports to the front. Give that a shot, maybe try all your usb devices
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![Confused Confused](https://forums.dolphin-emu.org/images/smilies/confused.gif)