There is a recurring set of VI's that keep showing up but it isn't always the same one. For example, a VI we wrote called "Write" which writes data to a file uses a number of instances of the Express function called Convert to Dynamic Data. When I bring up the main calling VI, even though it had no erros when I saved it, it is broken because the sub-VI "Write is not executable. And when I look at the "Write" Block DIagram, several of the Convert to Dynamic Data functions have been replaced by boxes with question marks. The context help says "Instance 11 22Saved "Write_June_8_1.vi was not found. I can fix this by wiring in new functions and the program will run as designed. But the next time I close it and reopen it, without even shutting doen LabVIEW, it will give me a similar error for sone others functions in either the main program or one of 2 or 3 other sub-vi's.
Other Express VI's I've seen this happen with include File Dialog and Time Dealy.