This copy of the Install OS X Mavericks application can't be verified
This erorr had occurred when i tried installing both Mavericks and Yosemite from a USB Jump Drive. After doing some research i realized that the date in the Macbook I had been trying to install the operating Systems on Date had been wrong, the battery was bad. so I opened the terminal and entered the current date at the time which was May 04. 2015 9:27 am. the command to enter the date is
I get a confirmation with the date i entered. Quite the terminal then go back and install Mavericks.