How to prevent Galaxy S4 from connecting as "Connected as Installer" instead of "Connected as Media Device"?
After connecting via USB and receive the message "connecting as installer" on your phone's screen, make sure you're phone isn't on the lock-screen and swipe down from the top (or at least on my Verizon device) you can access "USB PC connection" settings under the "ongoing" tab.  Check one of two options, MTP or PTP. This would be the same pull-down where you would quickly alter various settings, view downloads and be able to link to recent notifications. This will effectively switch out of installer mode so that you can access your phone's directory and that of any sub sequential micro SD card. Hope this helps.