The iMac OS X v10.8.5 Supplemental Update 1.0 is recommended for iMacs (Late 2013) using NVIDIA GeForce GT 750M graphics and running OS X Mountain Lion v10.8.5. This update:

• Fixes an issue that may cause external drives to be ejected after the computer goes to sleep
• Fixes an issue that may prevent certain USB Bluetooth adapters from working