1) Get to the upload a file area (via a File resource or restoring a backup) 2) Ensure post_max_size in php.ini is set lower than the file you are uploading (by default, this is 8M). 3) Drag that file onto the drag & drop area Before fix, Error "A required parameter (sesskey) was missing" should appear. After fix, Error "The uploaded file may exceed the post_max_size directive in php.ini." should appear 4) Click the Add button to show File Picker 5) Click 'Upload a file' 6) Upload the same file you attempted to drag & drop Before fix, Error "The uploaded file may exceed the post_max_size directive in php.ini." appears. After fix, Error "The uploaded file may exceed the post_max_size directive in php.ini." appears.