Please help.
Just like the title says I receive a
Unable to open ProbeDiag.dat Error=11 when starting up Mach3. It shows up for about 3 seconds at the start of the program then goes away. It happens when starting the profile I have set up. 
I should first let you know I just got a new smothstepper ESS up and running. This error just started at the same time I tried to load the first G code into it. Before this it would JOG just fine and start the spindle and control the speed.
The moment I loaded G code it would kick out an error Art Code 8877. Then the program would stop working. Windows 7 machine just for the CNC
Can someone please give me some in site to this. I don't know why it would have started after trying to load a G code that was working on the system and Jogging just fine 30 seconds before. 

bump

Hi camoit,
Did you find a solution, I've started having the same issue, it was working great and then all of a sudden the error started popping up?
Mine is Win7, USB smoothstepper and the latest Mach3 install.
Darc

Hi,

I had the same problem.   There was an access lock on the c:\Mach3\ProbeDiag.txt file and it prevented Mach3 from opening.

I deleted the c:\Mach3\ProbeDiag.txt file and Mach3 was able to open and run again.

Andy

Thanks aAndy!

The thing that solved it for me was closing the Notepad window that was opened by clicking "Edit G-code" from a previous Mach3 instance.

Not certain, but I'm suggesting this as a potential cause of the issue:
- "Edit G-code" in Mach3 --> opened Notepad window
- Closed Mach3 without closing Notepad window.
- Opened Mach3 again.  Error because Notepad window is still open.