Seth,

you said that "the installer works in 3 of 4 use cases. The 4th use case presents this error ("A decompression error has been detected" ..... [#99])."

Do you think it is possible that there is some kind of memory allocation problem in your DLL? As far as I can see, you are calling an external DLL. Please ignore if you do not call into a DLL. But if you do, perhaps the DLL corrupts the stack?

Would it be possible for you to temporary disable the DLL call(s) to see if this makes a difference? Other than that, I am running out of ideas. LSPack (the underlying de-(compression library) did tens of millions file installs over the last 20 years and it's nearly impossible that there is a bug in this rock solid component. So there must be another reason for the issue in your case.

Friedrich