VSDC video editor export problem: How do I cut the unwanted extra duration?

I have been using VSDC video editor for a long time but this is the first time I run into this problem. When I export the video, the output video turns out to be 5 seconds longer than how I edit it(also 5 sec longer than preview video). I tried everything I know but it always gives me 5 sec of blank scene in the end.Please help! Thx