Sometime ago, I posted an item asking for help on this topic. I have since discovered that the crash gets triggered when the order of the FRAMES in a form is changed. As to why this should be so and what happens to make changing the order of the frames critical, I have absolutely no idea. I have 5 main frames switched using a TAB control on the form. Each main frame contains further frames and other objects. To get this far, I did the following: 1 Restore to the last working non-crashing source backup. 2) Made backups every few changes. (Really painfully) 3) When VB started to crash on exit, I examined the formname.frm file using Notepad and noticed that the order of the BEGIN VB.FRAME framename statements for the main frames had changed compared to the previous version which did not crash. 4) Using the form editor, I restored the main frame order to that which did not crash and the crashing went away! The form needs a lot more development so proceeding on this basis is a pain. Does anybody understand this and might you maybe tell me what I might do to make the real problem go away? Can you tell me what the filename.frx file is for and can it be used to help diagnose the problem further?