I've written a batch action to crop a native 2:3 Canon image down to a 4:3 slide show size of 1024x768. The action appears to work but some of the resized images have areas of blank space where they were cropped when processed from Raws to large Jpegs before the downsize.
Could you be mixing in some portrait images into the batch. Handling Landscape and portraits in a batch process can be tricky. Also portrait 2:3 images cropped to a landscape 4:3 aspect ratio will not work well the resulting cropped composition will most likely be very poor.
thanks for the courtesy of your reply. Your suggestion is indeed wise, but
it isn't relevant to this case as all the original images were horizontals.
You expand the action so you can read the steps and setting recorded. You may see something in what was recorded that explains what is happening. If you can not solve to problem. Save the action set and upload it the the web and post a link to it. So I can download it and look at it.