Can't Delete Files within File Manager
If you are (attempting) to delete a file within the file manager either by itself or using the 'Delete' Selected' button and the files are still there, it is likely that you have the PHP 'Magic Quotes' settings turned on. This setting is only available in PHP versions 5.3 and earlier...and this symptom only occurs in Exponent v2.2.3patch4 and earlier.
The fix is to either update Exponent to a version more recent than v2.2.3patch4, OR update PHP to v5.4 or newer, OR change your PHP server settings (php.ini or phprc) to turn magic quotes OFF
; Magic quotes for incoming GET/POST/Cookie data. magic_quotes_gpc = Off