There is a crash, It seems eio_monitor will break if the file is a FIFO.
Had a look, maybe best to change the code in the filemanager??? Doesn't seem to be an ecore_file_is_fifo type tool.
This patch seems to work. No preview is shown if the file is a fifo. Otherwise E will crash.
I've attached the backtrace also in case you want to fix elsewhere or in EFL?