Are all of these videos on your C drive? If not, where are they?
What processor do you have and with how much RAM? How much free, clean, defragmented space is on your hard drive?
Hey Steve, thank you very much for your quick reply. Yes, they're on my C drive and I'm using a fairly fast processor with lots of free space and I've defragged...
But I did find something that worked...I copied the file so that I had the original still available and changed the file extension to .mov from mp4...and now everything is in sync. I read several theories as to why this works, but I still don't completely understand why...especially since several of the videos on the same memory card from the same camcorder were fine while others weren't. But it was easy as changing the file extension. Thank you, Steve!
Glad you found a solution. Though it's a shame it's a workaround rather than a fix.