Failure in launch() when upgrading from OptiX 4.0.3 --> 4.1.0

WIN7, CUDA8 - Driver Version 376.51 , VS2012

// Prepare to run
  double start, end_compile, end_AS_build;
  std::cerr << "Time to compile kernel: "<<end_compile-start<<" s.\n";
  m_context->launch(0,0); # <-- failure
  std::cerr << "Time to build AS      : "<<end_AS_build-end_compile<<" s.\n";
FATAL: appname.exe: Signal 11 was received.
f:\dd\vctools\crt_bld\self_64_amd64\crt\src\thr\mutex.c(38): mutex destroyed while busy
Caught exception during startup: Unknown error (Details: Function "_rtContextLaunch1D" caught C++ standard exception: device or resource busy)

Any idea what might cause this sort of error after changing OptiX versions to 4.1.0?

Sorry, but the provided information is not containing enough information to tell what’s going on.

What are your installed GPUs and how much VRAM do they have?
When upgrading OptiX versions anyway, why aren’t you using OptiX 5.0.0?
(Even 4.1.0 had been superceded by 4.1.1 which I also wouldn’t recommend anymore now that 5.0.0 is available. Just skim over the list of changes between individual versions on the latest version’s download site to see why.)
How about newer display drivers? Yours are over a year old.

If that doesn’t solve it:
What have been the times in your launch when it worked?
How big is the scene in number of primitives?