diff --git a/Source/RMG-Core/Config.hpp.in b/Source/RMG-Core/Config.hpp.in
index c1a35be6..a50ea7e9 100644
--- a/Source/RMG-Core/Config.hpp.in
+++ b/Source/RMG-Core/Config.hpp.in
@@ -14,8 +14,8 @@
 
 #ifndef PORTABLE_INSTALL
 #define CORE_INSTALL_PREFIX  "${CMAKE_INSTALL_PREFIX}"
-#define CORE_INSTALL_LIBDIR  "${CMAKE_INSTALL_LIBDIR}"
-#define CORE_INSTALL_DATADIR "${CMAKE_INSTALL_DATADIR}"
+#define CORE_INSTALL_LIBDIR  "${CMAKE_INSTALL_FULL_LIBDIR}"
+#define CORE_INSTALL_DATADIR "${CMAKE_INSTALL_FULL_DATADIR}"
 #endif // PORTABLE_INSTALL
 
 #endif // CORE_CONFIG_HPP
diff --git a/Source/RMG-Core/Directories.cpp b/Source/RMG-Core/Directories.cpp
index 4b124e14..1c13833e 100644
--- a/Source/RMG-Core/Directories.cpp
+++ b/Source/RMG-Core/Directories.cpp
@@ -244,9 +244,7 @@ std::filesystem::path CoreGetLibraryDirectory(void)
     }
     else
     {
-        directory = CORE_INSTALL_PREFIX;
-        directory += "/";
-        directory += CORE_INSTALL_LIBDIR;
+        directory = CORE_INSTALL_LIBDIR;
         directory += "/RMG";
     }
 #endif // PORTABLE_INSTALL
@@ -465,9 +463,7 @@ std::filesystem::path CoreGetSharedDataDirectory(void)
     }
     else
     {
-        directory = CORE_INSTALL_PREFIX;
-        directory += "/";
-        directory += CORE_INSTALL_DATADIR;
+        directory = CORE_INSTALL_DATADIR;
         directory += "/RMG";
     }
 #endif // PORTABLE_INSTALL