Peter,
if it *ONLY* happens in the .exe AND under the runtime,
instrument the code with lots of

#if CLOOKFORCRASH
  StrToFile(Padr(Program(), 20) + Str(LineNo()), "MyProt.Txt", .t.)
#endif

which is not as bad as it sounds if you are dodefaulting() to base methods regularly.
Still, if you are not 100% sure that it is the RUNTIME, I'ld first try a few times
by starting the IDE and Doing the exe: then Set Coverage should work, BUT Runtime-related
errors won't happen - only exe-related ones.

Also, if you already have some instrumented code (perfomance measurement probably,
at least my apps <g>), hook your profiling there.

If it is a large app, look into working on your code by program
to insert your instrumentation code.

Remember, a vcx is just a dbf and a prg is just text <g>.

HTH

thomas