Nope, not off the top of my head. Just seen it happen in the past. And I don't think the 128K software is making a call checking for RAM. It was explained to me on some old boards once upon a time when this came up, that the 512K allowed more of the program to reside in RAM than the software allowed and the 128K software did not know where to find it as it wasn't in the expected location. Then there was something about not writing to disk anything above a certain RAM address ... something that could happen on sloppy programs that did not take into account the availability of addition RAM, or so I was told. If this is in error about my understanding of this, let me know, Otherwise, I will keep an eye out for the software that does not seem to work properly under 512K. It would mainly be the very early stuff I have so easy enough to track down when I have some time.