Thank you all for the information. After the seventh try I was able to convert the file. It came in as a v2 but when successfully converted, it ended up as a filenamev2.mov. Strange, but it turned out OK. In reality, I think the crashing was because these MacBookPro Intel machines get very very hot and shut down or crash when they reach a certain temperature. I waited until the morning when the computer was cold and did the conversion first, before it could heat up, and it went through. Thank you all for the advice.
Stan