Speedlite won't flash on 60D! ???

LensMonkey wrote in post #16702586
It just doesn't seem to make sense. I know it's "communicating" with the camera, because I have confirmed that the camera detects an external flash being connected. Should an external flash automatically fire, regardless, when in green box mode?

That doesn't mean that there is any communication. All that means is that there is something in the hot shoe. Anything you put in there will trip a microswitch to tell the camera that the hot shoe is in use, nothing more. Sometimes the switch gets stuck and the camera thinks there is a flash attached when there is nothing there.

LensMonkey wrote in post #16702767
I always shoot in Manual mode, which is what it was set to in the begining. Is there specifically something else I need to do to set it to flash? First time using an external flash, so I just don't know. Thx.

It means Manual Mode on the flash.

a) Set the dial to Manual Mode shutter speed 1/125, some aperture, ISO 100. Mount the flash and turn it on.

b) Go to Menu/1st red menu/Flash Control>Press Set button

c) Make sure Enable Flash is selected

d) Roll down and select External Flash Function setting>press SET.

e) Select Flash Mode, press SET, select Manual press SET.

Take a photo. Does it work?

LensMonkey wrote in post #16702767
I always shoot in Manual mode, which is what it was set to in the begining. Is there specifically something else I need to do to set it to flash? First time using an external flash, so I just don't know. Thx.

No, not Manual exposure mode ... Manual Flash Control mode as opposed to TTL or E-TTL. The menu gives you a choice of one of the three options for an external flash.

Is the flash in "Slave" mode?

rrblint wrote in post #16702977
Is the flash in "Slave" mode?

As indicated by using a setting of "S1" or "S2" instead of the "M" (referring to setting on the flash unit).