CKEditor filemanager getting stuck uploading files?

Question

I'm using CKEditor and it's inbuilt filemanager to allow people to change content/upload images to their site.

Everything works fine, except the file manager, if you upload an image it gets stuck loading claiming that it's "Transferring Data" and will continue to display this loader unless the page is refreshed.

The strange thing is that, on reloading the page you can see the file has been uploaded successfully.

Has anybody experienced this issue before? Does anybody have any idea what could be causing this behaviour?

Answer 1

Turned out there were a couple of outdated files that crept into the filemanager directory on the live site, not sure how or why, but that was what caused this issue.