I have not yet got myself to the point that I'm actually editing the .pst file. However, I was concerned about my habit of forgetting to make sure that I had a different D comp. number than my Tool number when it came to the older machines that don't have a separate offsett for diameter comps. You know what happens when your diameter comp is picked up and your control doesn't have a seperate D offset from the length offset. Believe me I love your idea of putting in pop up windows to warn of potential problems and someday I will do the same. Untill then I found a way that takes away most of my trouble with the D comp. thing. I simply went into the control definition and clicked on tool. There is a place to check for "Add to tool", then one field for length, and the other for diameter. For the older machines that don't have the seperate offset for diameter comps. I add the amount of the magazine capacity ( you can use any number though ) to the diameter field. Now when you create a new tool MasterCam will fill in the diameter offset in your tool creation page automatically. If you entered 20 to "Add to tool" and you create an end mill with the tool number 4, it will automatically fill in the diameter field with the number 34. Tools already created in an existing file may not change real time, but newly created tools will. Now I could swear that in X6 I could change this setting for only the file currently opened if I opened it from "Machine group properties/files/edit. This wouldn't change the setting for new files. When I just tried it in X7, it didn't seem to work unless I made the change from Settings/machine definition manager. When you make the change that way, it changes that machine setting for every file after that. There may be a pick when you change the control definition from Settings/machine definition manager that will only change the file you currently have opened, I don't know. When I find a method that works for a task I often won't try other settings for quite some time. As I said, I'm just getting started with getting the code to read the way I want it to. I hope this made enough sense to use it.