Can not emty the trask?
iMac (27-inch, Late 2013), iOS 8.3, 24 GB.memory. 3.5 GHZ intel Cor I7
Try my software Force Empty Trash:
http://www.macmaps.com/software.html
* Links to my pages may give may give me compensation.
P.S. You posted to the wrong operating system forum. iOS doesn't run on 2013 iMacs.
Go to Apple menu -> About This Mac to verify your operating system, before choosing your forum from here:
Can not emty the trask?