It was actually only about 160 posts, but since it imports all the media first, it wasn’t getting to it. I read around that the importer was smart enough not to import duplicate content, so I kept re-trying it. It took about 4 times, but it finally completed the upload.
My trick was to check on the media library in a different tab, and each time it stopped increasing, I’d refresh the page that was importing everything. That way I didn’t have to reassign all of the authors each time.
