I realize I am new here but not totally ignorant to cnc machines.  I just built mine and was trying to ring it out and came upon an unexpected problem.  I set up the e-stop as directed but I keep getting an error saying external e-stop requested.

Here is the set up on my machine.

all limit switches and e-stop are in series and have been verified

in the mach3 config, the e-stop is set up for the correct pin for my break out board
the active low is enabled
the emergency stop radio button in the diagnostic screen stays grey
when any limit switch or the e-stop switch is pushed the emergency radio button turns red
with the emergency stop or any limit switch activated the machine will not reset
with the machine in normal (no limit switch or emergency stop activated) the machine will reset but fault out again in about 2 seconds with the "extrnal e-stop requested" error

The switchs and e-stop have been verified so I have no idea where to look now.  I realize this may be a noob question and I apologize but any help will be greatly appreciated.  Thanks

Sounds like you have noise on the inputs. Low voltage wiring such as these should be properly shielded and grounded to try and stop noise affecting them. You can try some Debounce Interval (config menu then General Config) but the best option is proper shielding.
Hood

I believe you are correct about the noise.  I still have that same problem but not sure now how to get rid of it.  I have found when exactly the problem starts and the steps I've taken.

1.     Re did the wiring in the control box with shielded wire and the shield hooked to ground for each limit switch and e-stop
2.     Double checked the shield in the cable going from the control box to tool...it too is grounded.

Checked out all switches and everything worked great until I "ENABLED" the stepper in the software.  As soon as I did that the error popped up and is doing the same as before.

Any suggestions as to what to do in this situation.

When you say

and the shield hooked to ground for each limit switch and e-stop

How have you got this connected? Is it actually to a single point or do you have it connected to a ground connection on your breakout board or somewhere?
Hood

I used a db9 connector at the control box.  I'm using 3 cables, 2 conductor shielded for each of the 3 home switches.  I have all the limit switches and e-stop tied in series with shielded cable like the others.  I'm using 8 of the 9 pins of the db9 for the home and estop switches.  I have the shield wires tied together and hooked to the last pin of the db9.  that pin is tied to ground on the breakout board.  The shield on the multi conductor cable going to the tool is connected to ground or shield pin on the db9.

I have been checking further to try and isolate the problem as well.  I separated all the cables from the control box to the tool with the same results.  I removed the db9 connector from to control box and moved it away from the stepper drivers with the same results.  It is still when the enable is made active.  I even went as far as to disconnect each motor and with all 4 motors disconnected the problem is solved.  I did not use shielded cables for the motors as I didn't figure I needed them.   I have been trying to isolate where the noise is entering and drawing a blank.

Shielding should be connected direct to a stud in your cabinet and that stud connected to Earth on your mains.
Hood

Try connecting a 0.1uF ceramic capacitor across your switch wires at the breakout board.
I had trouble with this early on in my build. I was having to run a very high debounce value and after fitting these caps, I don't run any value and don't get false triggers.
I don't run any shielded cables for motors or switches.

The caps did the trick.  I should have known that lol. Thanks for the help and it's working great now