Quote Originally Posted by charlieuk View Post
possibly, I ran the same file today I did not have any problems
I still think it is the PC grabbing resources. Mach3 may not be able to detect it if it is halted by the OS. Another thing I thought about is the look ahead buffer. I have a weak memory that I had similar issues a long time ago while I used the parallel port of a Windows XP computer. After I changed to USB the problem was gone. My current laptop has Windows 10 and anti virus on, it has Internet connection as well and don't seem to have problems. Is your computer still running under XP? Is it old? Are you using the parallel port?