Why might a file only be partially uploaded?
I am improving error-handling in my PHP file upload script and am trying to figure out how to handle UPLOAD_ERR_PARTIAL properly.
Should I prompt the user to try uploading the file again, or should I inform them that there is a more severe problem which is preventing them from uploading a possibly legitimate file?
This is usually caused by the user canceling the upload.
You should prompt them to try again and if problems continue to contact the site owners, including as much detail as possible.