diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4a6364a5dee3331d77a01656c6c97b9d3e000fcd..792dbc88f70e7f8809bf78a7e330bd408cc27fd7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -34,17 +34,21 @@ if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
   # Set the possible values of build type for cmake-gui
   set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS
     "Debug" "Release" "MinSizeRel" "RelWithDebInfo")
-endif()
+endif(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
 
 # enable warnings and disallow non-standard language
 set(CMAKE_CXX_FLAGS "-Wall -pedantic -Wextra -Wno-ignored-qualifiers")
 set(CMAKE_CXX_FLAGS_DEBUG "-O0 -g")
-set(CMAKE_CXX_FLAGS_RELEASE "-O3 -g") 
+set(CMAKE_CXX_FLAGS_RELEASE "-O3 -g") # -O2 would not trade speed for size, neither O2/3 use fast-math 
 
 # clang produces a lot of unecessary warnings without this:
 add_compile_options("$<$<CXX_COMPILER_ID:Clang>:-Wno-nonportable-include-path>") 
 
-  
+# check if we are on OSX:
+if (APPLE)
+  add_compile_definitions (CORSIKA_OSX)
+endif (APPLE)
+
 # unit testing coverage, does not work yet
 #include (CodeCoverage)
 ##set(COVERAGE_LCOV_EXCLUDES 'Documentation/*')
diff --git a/Framework/Cascade/Cascade.h b/Framework/Cascade/Cascade.h
index ae8b18932ca769cd1f716d54808078820b390842..ba05bd78e444e59e542972ce2420e485a4a18d6f 100644
--- a/Framework/Cascade/Cascade.h
+++ b/Framework/Cascade/Cascade.h
@@ -48,7 +48,6 @@ namespace corsika::cascade {
       while (!fStack.IsEmpty()) {
         while (!fStack.IsEmpty()) {
           auto pNext = fStack.GetNextParticle();
-          //std::cout << pNext
           Step(pNext);
         }
         // do cascade equations, which can put new particles on Stack,
diff --git a/Processes/Sibyll/Decay.h b/Processes/Sibyll/Decay.h
index ec776afcd5c2d974936c2e4ec82d5301e83b85bf..13c6a3ebc094b7618ca694fb7b2b74786571cdcc 100644
--- a/Processes/Sibyll/Decay.h
+++ b/Processes/Sibyll/Decay.h
@@ -169,7 +169,10 @@ namespace corsika::process {
         using corsika::geometry::Point;
         using namespace corsika::units::si;
 
+	// TODO: this should be done in a central, common place. Not here..
+#ifndef CORSIKA_OSX
         feenableexcept(FE_INVALID);
+#endif
 
         fCount++;
         SibStack ss;
@@ -216,7 +219,10 @@ namespace corsika::process {
         // empty sibyll stack
         ss.Clear();
 
+	// TODO: this should be done in a central, common place. Not here..
+#ifndef CORSIKA_OSX
         fedisableexcept(FE_INVALID);
+#endif
       }
     };
   } // namespace sibyll