couple things i found direct quotes from threads
open the dial pad and dial *#0808#
then under Qualcomm USB or USB settings it should be on MTP or MTP+ADB
Unplug phone from PC.
Enable Developer Options:
MENU>SETTINGS>ABOUT PHONE>
Scroll down to the "greyed out" "BUILD NUMBER"
and tap it 5 times (possibly 7), you will see little
alerts telling you how many more times to tap.
Now go back to:
MENU>SETTINGS>DEVELOPER OPTIONS should be visible now!
Under developer options settings, check the box "USB DEBUGGING"
Next download the Samsung Galaxy USB drivers onto
your PC.
Download Center: Download Software, Firmware, Drivers & Manuals | Samsung
Choose your model and carrier.
Install and reboot.
Now when you connect your Galaxy it will either auto open
Windows Explorer (if PC), or if not, pull down the taskbar
on your droid, and under USB connection, you can select
Media Transer option.. MTD I think? or MTP. I can't
verify because it doesn't appear anymore after the 4.3 update
Give it about 30 seconds to connect, and it should appear
in Windows My Computer list of available drives.