diff --git a/CMake/mitkFunctionCheckCompilerFlags.cmake b/CMake/mitkFunctionCheckCompilerFlags.cmake
index 3df3f41ad5..abf3d13f88 100644
--- a/CMake/mitkFunctionCheckCompilerFlags.cmake
+++ b/CMake/mitkFunctionCheckCompilerFlags.cmake
@@ -1,80 +1,98 @@
 #
 # Helper macro allowing to check if the given flags are supported
 # by the underlying build tool
 #
 # If the flag(s) is/are supported, they will be appended to the string identified by RESULT_VAR
 #
 # Usage:
 #   mitkFunctionCheckCompilerFlags(FLAGS_TO_CHECK VALID_FLAGS_VAR)
 #
 # The above example uses the C++ compiler to check the flags. To individually check with
 # the C and C++ compiler, use:
 #
 #   mitkFunctionCheckCompilerFlags2(FLAGS_TO_CHECK VALID_C_FLAGS_VAR VALID_CXX_FLAGS_VAR)
 #
 # Example:
 #
 #   set(myflags)
 #   mitkFunctionCheckCompilerFlags("-fprofile-arcs" myflags)
 #   message(1-myflags:${myflags})
 #   mitkFunctionCheckCompilerFlags("-fauto-bugfix" myflags)
 #   message(2-myflags:${myflags})
 #   mitkFunctionCheckCompilerFlags("-Wall" myflags)
 #   message(1-myflags:${myflags})
 #
 #   The output will be:
 #    1-myflags: -fprofile-arcs
 #    2-myflags: -fprofile-arcs
 #    3-myflags: -fprofile-arcs -Wall
 
 include(TestCXXAcceptsFlag)
 include(CheckCXXCompilerFlag)
 include(CheckCCompilerFlag)
 
 function(mitkFunctionCheckCompilerFlags CXX_FLAG_TO_TEST RESULT_VAR)
 
   if(CXX_FLAG_TO_TEST STREQUAL "")
     message(FATAL_ERROR "CXX_FLAG_TO_TEST shouldn't be empty")
   endif()
 
   # Internally, the macro CMAKE_CXX_ACCEPTS_FLAG calls TRY_COMPILE. To avoid
   # the cost of compiling the test each time the project is configured, the variable set by
   # the macro is added to the cache so that following invocation of the macro with
   # the same variable name skip the compilation step.
-  # For that same reason, ctkFunctionCheckCompilerFlags function appends a unique suffix to
+  # For that same reason, the mitkFunctionCheckCompilerFlags function appends a unique suffix to
   # the HAS_FLAG variable. This suffix is created using a 'clean version' of the flag to test.
   string(REGEX REPLACE "[, \\$\\+\\*\\{\\}\\(\\)\\#]" "" suffix ${CXX_FLAG_TO_TEST})
   CHECK_CXX_ACCEPTS_FLAG(${CXX_FLAG_TO_TEST} HAS_FLAG_${suffix})
 
   if(HAS_FLAG_${suffix})
     set(${RESULT_VAR} "${${RESULT_VAR}} ${CXX_FLAG_TO_TEST}" PARENT_SCOPE)
   endif()
 
 endfunction()
 
 function(mitkFunctionCheckCompilerFlags2 FLAG_TO_TEST C_RESULT_VAR CXX_RESULT_VAR)
 
   if(FLAG_TO_TEST STREQUAL "")
     message(FATAL_ERROR "FLAG_TO_TEST shouldn't be empty")
   endif()
 
-  # Internally, the macro CMAKE_CXX_ACCEPTS_FLAG calls TRY_COMPILE. To avoid
+  # Clear all flags. If not, existing flags triggering warnings might lead to
+  # false-negatives when checking for certain compiler flags.
+  set(CMAKE_C_FLAGS )
+  set(CMAKE_C_FLAGS_DEBUG )
+  set(CMAKE_C_FLAGS_MINSIZEREL )
+  set(CMAKE_C_FLAGS_RELEASE )
+  set(CMAKE_C_FLAGS_RELWITHDEBINFO )
+  set(CMAKE_CXX_FLAGS )
+  set(CMAKE_CXX_FLAGS_DEBUG )
+  set(CMAKE_CXX_FLAGS_MINSIZEREL )
+  set(CMAKE_CXX_FLAGS_RELEASE )
+  set(CMAKE_CXX_FLAGS_RELWITHDEBINFO )
+
+  # Internally, the macro CMAKE_CXX_COMPILER_FLAG calls TRY_COMPILE. To avoid
   # the cost of compiling the test each time the project is configured, the variable set by
   # the macro is added to the cache so that following invocation of the macro with
   # the same variable name skip the compilation step.
-  # For that same reason, ctkFunctionCheckCompilerFlags function appends a unique suffix to
-  # the HAS_FLAG variable. This suffix is created using a 'clean version' of the flag to test.
-  string(REGEX REPLACE "[, \\$\\+\\*\\{\\}\\(\\)\\#]" "" suffix ${FLAG_TO_TEST})
+  # For that same reason, the mitkFunctionCheckCompilerFlags2 function appends a unique suffix to
+  # the HAS_CXX_FLAG and HAS_C_FLAG variable. This suffix is created using a 'clean version' of the
+  # flag to test. The value of HAS_C(XX)_FLAG_${suffix} additonally needs to be a valid
+  # pre-processor token because CHECK_CXX_COMPILER_FLAG adds it as a definition to the compiler
+  # arguments. An invalid token triggers compiler warnings, which in case of the "-Werror" flag
+  # leads to false-negative checks.
+  string(REGEX REPLACE "[/-]" "_" suffix ${FLAG_TO_TEST})
+  string(REGEX REPLACE "[, \\$\\+\\*\\{\\}\\(\\)\\#]" "" suffix ${suffix})
   CHECK_CXX_COMPILER_FLAG(${FLAG_TO_TEST} HAS_CXX_FLAG_${suffix})
 
   if(HAS_CXX_FLAG_${suffix})
     set(${CXX_RESULT_VAR} "${${CXX_RESULT_VAR}} ${FLAG_TO_TEST}" PARENT_SCOPE)
   endif()
 
   CHECK_C_COMPILER_FLAG(${FLAG_TO_TEST} HAS_C_FLAG_${suffix})
 
   if(HAS_C_FLAG_${suffix})
     set(${C_RESULT_VAR} "${${C_RESULT_VAR}} ${FLAG_TO_TEST}" PARENT_SCOPE)
   endif()
 
 endfunction()