diff --git a/CMakeLists.txt b/CMakeLists.txt
index 56e935eb..154ea52e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,6 +9,7 @@ option(ASlibs "build optional ASlibs" OFF)
 option(BMWlibs "build optional BMWlibs" OFF)
 option(BNMRlibs "build optional beta-NMR libs" OFF)
 option(qt_based_tools "try to install Qt based tools (musredit, musrWiz, musrStep, mupp)" ON)
+option(try_OpenMP "try to use OpenMP if available" ON)
 
 #--- check for all the needed packages ----------------------------------------
 
@@ -43,10 +44,12 @@ find_package(FFTW3 REQUIRED)
 find_package(LibXml2 REQUIRED)
 
 #--- check for OpenMP ---------------------------------------------------------
-find_package(OpenMP)
-if (OpenMP_FOUND)
-  add_definitions(-DHAVE_GOMP)
-endif (OpenMP_FOUND)
+if (try_OpenMP)
+  find_package(OpenMP)
+  if (OpenMP_FOUND)
+    add_definitions(-DHAVE_GOMP)
+  endif (OpenMP_FOUND)
+endif (try_OpenMP)
 
 #--- check for Qt -------------------------------------------------------------
 if (qt_based_tools)
@@ -107,6 +110,9 @@ message(" GSL     found in ${GSL_INCLUDE_DIRS}")
 message(" BOOST   found in ${Boost_INCLUDE_DIRS}")
 message(" LibXML2 found in ${LIBXML2_INCLUDE_DIR}")
 message(" ROOT    found in ${ROOT_INCLUDE_DIRS}")
+if (OpenMP_FOUND)
+  message(" OpenMP  found (version ${OpenMP_VERSION})")
+endif (OpenMP_FOUND)
 
 if (nexus)
   message("")
@@ -121,7 +127,19 @@ if (BMWlibs)
 endif (BMWlibs)
 
 message("")
-message(" Qt      found in  ${Qt5Core_INCLUDE_DIRS} (Version: ${Qt5Core_VERSION})")
+if (qt_based_tools)
+  if (Qt5Core_FOUND)
+    message(" Qt      found in  ${Qt5Core_INCLUDE_DIRS} (Version: ${Qt5Core_VERSION})")
+  else (Qt5Core_FOUND)
+    if (Qt4_FOUND)
+      message(" Qt      found in  ${Qt4_INCLUDE_DIRS} (Version: ${Qt4_VERSION})")
+    else (Qt4_FOUND)
+      if (QT_FOUND)
+        message(" Qt      found in  ${QT_INCLUDE_DIRS} (Version: ${QT_VERSION})")
+      endif (QT_FOUND)
+    endif (Qt4_FOUND)
+  endif (Qt5Core_FOUND)
+endif (qt_based_tools)
 message("")
 message(" Features:")
 message(" ---------")
diff --git a/src/classes/CMakeLists.txt b/src/classes/CMakeLists.txt
index 6d4f952d..619d9864 100644
--- a/src/classes/CMakeLists.txt
+++ b/src/classes/CMakeLists.txt
@@ -106,7 +106,6 @@ if (nexus)
   set(DependOnLibs ${DependOnLibs} ${LIBNEXUS_LIBRARY})
   set(DependOnLibs ${DependOnLibs} PNeXus)
 endif (nexus)
-message("debug> OpenMP_FOUND: ${OpenMP_FOUND}, libs: ${OpenMP_CXX_LIBRARIES}")
 if (OpenMP_FOUND)
   set(DependOnLibs ${DependOnLibs} ${OpenMP_CXX_LIBRARIES})
 endif (OpenMP_FOUND)
diff --git a/src/external/MuSR_software/Class_MuSR_PSI/CMakeLists.txt b/src/external/MuSR_software/Class_MuSR_PSI/CMakeLists.txt
index 122feb9b..0c5d59d4 100644
--- a/src/external/MuSR_software/Class_MuSR_PSI/CMakeLists.txt
+++ b/src/external/MuSR_software/Class_MuSR_PSI/CMakeLists.txt
@@ -9,6 +9,15 @@ set(PSIBIN_VERSION "0.1.0")
 set(PSIBIN_LIBRARY_NAME "Class_MuSR_PSI")
 configure_file("Class_MuSR_PSI.pc.in" "Class_MuSR_PSI.pc" @ONLY)
 
+#--- OS dependent pre-compiler settings for PSI-BIN ---------------------------
+if (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
+  add_definitions(-D__linux__)
+elseif (${CMAKE_SYSTEM_NAME} STREQUAL "Darwin")
+  add_definitions(-D_Darwin_)
+elseif (${CMAKE_SYSTEM_NAME} STREQUAL "Windows")
+  add_definitions(-D_WIN32)
+endif (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
+
 #--- lib creation -------------------------------------------------------------
 add_library(Class_MuSR_PSI SHARED MuSR_td_PSI_bin.cpp)