My screen shot function stopped working yesterday on my Samsung Galaxy S5

[AC Question]

Screen shot function on my Samsung Galaxy S5 stopped working yesterday. I keep getting a pop-up saying that system UI has stopped. What is system UI and how do I fix my issue?

 

[ironass]

Download and re-flash the firmware for your model of Galaxy S5, CSC and Product codes by carefully following the instructions and video in #1.11 of 42 Galaxy S5 models - Dummies Guide