Initial account creation hangs

Question

We've encountered this in nearly every new Yosemite machine we've unboxed in the last month (about 8 total, from Mac Minis to MacBook Pros). On first boot, when we create the initial user account it hangs. The progress wheel stops spinning and the Mac won't do anything. We've let them sit for up to 15 minutes and it never gets past that stage. If we hard reboot, Setup Assistant starts over but we can't create a user account with the same name we originally tried to use, because in fact the account was created. Once we complete Setup Assistant, which does not hang the second time through, we find that both accounts have been created.
We've tried this with and without first joining a WiFi network. Anyone else experiencing this? Anyone have a workaround other than what we do now, which is just hard reboot and add another account?

Answer 1

Since they're new machines, contact Apple's Support and let them deal with the problem. You have 90-day free phone support, 3 years if you bought the AppleCare Protection Plan.
27" i7 iMac (Mid 2011) refurb, OS X Yo (10.10.1), Mavs, ML & SL, G4 450 MP w/10.5 & 9.2.2