In doing this I have noted. o creating small trivial cases seemed to work. o when I combined the test case files to a single file, it worked In trying to create the test case I figured out what caused the crash, Basically I had included text archive in all the compilation units but the binary archive _only_ in the file where I was outputting to the disk. When I included the binary archive in _all_ the compilation units that were being serialized, the test worked. I am not sure how common this case is, but gcc compiler/linker gave no warnings Maybe this need to be added as a gotcha in the documentation? DON'T stop now ! something like this is probably due to some include file missing somewhere inside the library or something like that. Keep boiling it down to a small example that I can't use to investigate. Robert Ramey