Q: using migration assistant, and it appears to be 'stuck' on one minute to go - what should I do?

I am using Migration assistant to migrate date from a Win7 PC to a MACBook Air & the progress counter appears to be 'stuck' with the message that there is 'less than one minute to complete' (migration - but that message has remained unchanged for over one hour - looking for advise on next steps - wait & see (but for how long) or cancel & start again?  The assistant has been running for approx 12 hours now...