Photoshop stuck on export window

Anyone know how to get around this? 

Every so often when I'm exporting photos as jpegs, it gets stuck processing on the export window. I have to keep closing the window to then save my file as a psd, then close and reopen photoshop to try again. Doesn't happen all the time but gets very annoying when working on larger projects and having to go through this every 10 or so photos