I recently did a full upgrade on AstroBerry so will try this again as I've not had a chance to do much testing since my original post.

One thing to note from memory I had the error in the following two circumstances (1) one target with a lot of images all going into the same folder, and (2) multiple targets with different folders.

I am sure there are some out there asking why take hundreds of images of a target like this, but lucky imaging can be very good for splitting double stars.