No good for me. I don't have anti-virus, yet I can't get past the "Backing Up" phase. The most I get is the progress bar moving about 1 millimeter every 10 minutes. Still in a state of epic fail 3+ hours later.
I disabled my antivirus software at work (Microsoft Forefront) and it happened to work after that. I still think I got lucky and it just happened to work that time (5th time) but maybe it wasn't a coincidence.