I can eliminate the error is I remove the Ethernet, Robot_Control, SD, TFT, and WiFi libraries.
Invalid library found in C:\Program Files (x86)\arduino-1.6.6\libraries\Ethernet: Library can't use both 'src' and 'utility' folders.
The Keypad library actually had 'src' and 'utility' folders. I removed them and the message went away.
The error is supposed to be caused when a library has both src and utility folders in the library root folder but the strange thing is that none of those libraries have that issue. Another user reported the same issue was solved by renaming the utility folder in the firmata library here: http://forum.arduino.cc/index.php?topic=357312.msg2464456#msg2464456. The firmata library also doesn't have a src and utility folder in the root folder. So I think it's a bug with the Arduino IDE but on my installation I don't have the issue. If anyone finds more information please report it here so we can try to find the cause and submit an issue report to the developers.
If anyone is having this issue try this:Sketch > Include Library > Manage Libraries...CloseYou should see a message in the console that looks something like:
What console are you refering to?
I don't see anything about invalid libraries with, or without a suspect library included. Even with a complete restart between tests.