diff --git a/cmake/cmake-modules/FindEigen3.cmake b/cmake/cmake-modules/FindEigen3.cmake
index a93fa4b000..61893f8141 100644
--- a/cmake/cmake-modules/FindEigen3.cmake
+++ b/cmake/cmake-modules/FindEigen3.cmake
@@ -67,7 +67,7 @@ if (EIGEN3_INCLUDE_DIR)
 else (EIGEN3_INCLUDE_DIR)
 
  
-   if (${EIGEN_ROOT} STREQUAL "" )
+   if ("${EIGEN_ROOT}" STREQUAL "" )
        message(ERROR " Please set your EIGEN_ROOT install location")
    endif()