Since I upgraded my gs4 to 4.3 I keep getting a popup saying "Security information. an application attempted to access system on your device without authorization. This attempt has been blocked. Deleting applications obtained from unauthorized sources may improve security.

All of my apps are legit ones and all paid for

It gives me the option of cancel or view apps , tapping view apps just lists all the apps on my phone and not the one that is supposed to have caused the security problem.

I have not installed knox (i think its called) that came in 4.3.

Anybody else having this or know anything about it at all ??