diff --git a/Modules/FindMatlab.cmake b/Modules/FindMatlab.cmake
index 939f7969d..028bf5a99 100644
--- a/Modules/FindMatlab.cmake
+++ b/Modules/FindMatlab.cmake
@@ -134,7 +134,8 @@
 #   returns the suffix to be used for the mex files
 #   (platform/architecture dependant)
 # :command:`matlab_get_version_from_matlab_run`
-#   returns the version of Matlab, given the full directory of the Matlab program.
+#   returns the version of Matlab, given the full directory of the Matlab
+#   program.
 #
 #
 # Known issues
@@ -1064,7 +1065,7 @@ if(Matlab_ROOT_DIR)
     endif()
   else()
     # NOTFOUND indicates the code below to search for the version automatically
-    if(NOT DEFINED Matlab_VERSION_STRING_INTERNAL)
+    if("${Matlab_VERSION_STRING_INTERNAL}" STREQUAL "")
       list(APPEND _matlab_possible_roots "NOTFOUND" ${Matlab_ROOT_DIR}) # empty version
     else()
       list(APPEND _matlab_possible_roots ${Matlab_VERSION_STRING_INTERNAL} ${Matlab_ROOT_DIR}) # cached version
diff --git a/Tests/RunCMake/FindMatlab/MatlabTest2-result.txt b/Tests/RunCMake/FindMatlab/MatlabTest2-result.txt
new file mode 100644
index 000000000..573541ac9
--- /dev/null
+++ b/Tests/RunCMake/FindMatlab/MatlabTest2-result.txt
@@ -0,0 +1 @@
+0
diff --git a/Tests/RunCMake/FindMatlab/MatlabTest2-stderr.txt b/Tests/RunCMake/FindMatlab/MatlabTest2-stderr.txt
new file mode 100644
index 000000000..9abb766ce
--- /dev/null
+++ b/Tests/RunCMake/FindMatlab/MatlabTest2-stderr.txt
@@ -0,0 +1 @@
+.*
\ No newline at end of file
diff --git a/Tests/RunCMake/FindMatlab/MatlabTest2.cmake b/Tests/RunCMake/FindMatlab/MatlabTest2.cmake
new file mode 100644
index 000000000..d5b0e6db1
--- /dev/null
+++ b/Tests/RunCMake/FindMatlab/MatlabTest2.cmake
@@ -0,0 +1,9 @@
+cmake_minimum_required (VERSION 2.8.12)
+enable_testing()
+project(findmatlab_runcmake_test2)
+
+if(NOT DEFINED matlab_required)
+  set(matlab_required REQUIRED)
+endif()
+
+find_package(Matlab ${matlab_required} COMPONENTS MX_LIBRARY)
diff --git a/Tests/RunCMake/FindMatlab/RunCMakeTest.cmake b/Tests/RunCMake/FindMatlab/RunCMakeTest.cmake
index 33dbb772c..f0eb6b4bb 100644
--- a/Tests/RunCMake/FindMatlab/RunCMakeTest.cmake
+++ b/Tests/RunCMake/FindMatlab/RunCMakeTest.cmake
@@ -1,3 +1,51 @@
 
 include(RunCMake)
 run_cmake(MatlabTest1)
+
+if(RunCMake_GENERATOR MATCHES "Make" AND UNIX)
+  # Use a single build tree for a few tests without cleaning.
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/RerunFindMatlab-build-init)
+  set(RunCMake_TEST_NO_CLEAN 1)
+  file(REMOVE_RECURSE "${RunCMake_TEST_BINARY_DIR}")
+  file(MAKE_DIRECTORY "${RunCMake_TEST_BINARY_DIR}")
+
+  message(STATUS "RerunFindMatlab: first configuration to extract real Matlab_ROOT_DIR")
+  set(RunCMake_TEST_OPTIONS "-Dmatlab_required=REQUIRED")
+  run_cmake(MatlabTest2)
+
+  message(STATUS "RerunFindMatlab: flushing the variables")
+  execute_process(COMMAND
+                    ${CMAKE_COMMAND} -L ${RunCMake_TEST_BINARY_DIR}
+                    RESULT_VARIABLE _MatlabTest2_error
+                    OUTPUT_VARIABLE _MatlabTest2_output)
+  if(NOT _MatlabTest2_error EQUAL 0)
+    message(FATAL_ERROR "RerunFindMatlab: cannot list the variables ...")
+  endif()
+
+  string(REGEX MATCH "Matlab_ROOT_DIR.+=([^\r\n]+)" _matched ${_MatlabTest2_output})
+
+  set(Matlab_ROOT_DIR_correct "${CMAKE_MATCH_1}")
+  if(Matlab_ROOT_DIR_correct STREQUAL "")
+    message(FATAL_ERROR "RerunFindMatlab: cannot extract Matlab_ROOT_DIR")
+  endif()
+  message(STATUS "RerunFindMatlab: detected correct Matlab_ROOT_DIR=${Matlab_ROOT_DIR_correct}")
+
+  message(STATUS "RerunFindMatlab: change configuration, incorrect Matlab_ROOT_DIR setting")
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/RerunFindMatlab-build-second)
+  set(RunCMake_TEST_NO_CLEAN 1)
+  file(REMOVE_RECURSE "${RunCMake_TEST_BINARY_DIR}")
+  file(MAKE_DIRECTORY "${RunCMake_TEST_BINARY_DIR}")
+
+  set(RunCMake_TEST_OPTIONS "-DMatlab_ROOT_DIR=/" "-Dmatlab_required=")
+  run_cmake(MatlabTest2)
+
+  message(STATUS "RerunFindMatlab: fixing configuration with correct Matlab_ROOT_DIR setting")
+  set(RunCMake_TEST_OPTIONS "-DMatlab_ROOT_DIR=${Matlab_ROOT_DIR_correct}") # required this time?
+  run_cmake(MatlabTest2)
+
+  # no target on this test
+  run_cmake_command(MatlabTest2 ${CMAKE_COMMAND} --build .)
+
+  unset(RunCMake_TEST_BINARY_DIR)
+  unset(RunCMake_TEST_NO_CLEAN)
+endif()