Geoff, this probably isn't much help to you, but we have a commercial application that relies heavily on VFP timers. We've found that on approximately 2% of computers, regardless of the OS, the timers will run to a point and then stop. We've not been able to figure out why. Sometimes upgrading to the latest OS patches has helped, but not in every case. I would suggest trying your program on another computer to see if you run into the same issue.

Our solution was a re-write in a language that allowed for multi-threading and that was more suitable to the application, in our case, Java.

Good luck and let me know if anything changes when you try it on another computer.

-Matt