diff --git a/emsdk b/emsdk
index 4e48f13..88eda3b 100755
--- a/emsdk
+++ b/emsdk
@@ -674,6 +674,8 @@ class Tool:
   def expand_vars(self, str):
     if WINDOWS and '%MSBuildPlatformsDir%' in str:
       str = str.replace('%MSBuildPlatformsDir%', find_msbuild_dir())
+    if '%cmake_build_type%' in str:
+      str = str.replace('%cmake_build_type%', (self.cmake_build_type + '/') if WINDOWS else '')
     if '%installation_dir%' in str:
       str = str.replace('%installation_dir%', sdk_path(self.installation_dir()))
     str = str.replace('%.exe%', '.exe' if WINDOWS else '')
diff --git a/emsdk_manifest.json b/emsdk_manifest.json
index 035ac26..53fa176 100644
--- a/emsdk_manifest.json
+++ b/emsdk_manifest.json
@@ -439,7 +439,7 @@
     "version": "incoming",
     "url": "git://github.com/kripken/emscripten.git",
     "git_branch": "incoming",
-    "activated_cfg": "EMSCRIPTEN_ROOT='%installation_dir%';EMSCRIPTEN_NATIVE_OPTIMIZER='%installation_dir%/tools/optimizer_build/RelWithDebInfo/optimizer%.exe%'",
+    "activated_cfg": "EMSCRIPTEN_ROOT='%installation_dir%';EMSCRIPTEN_NATIVE_OPTIMIZER='%installation_dir%/tools/optimizer_build/%cmake_build_type%optimizer%.exe%'",
     "activated_path": "%installation_dir%",
     "activated_env": "EMSCRIPTEN=%installation_dir%",
     "cmake_build_type": "RelWithDebInfo",
@@ -450,7 +450,7 @@
     "version": "master",
     "url": "git://github.com/kripken/emscripten.git",
     "git_branch": "master",
-    "activated_cfg": "EMSCRIPTEN_ROOT='%installation_dir%';EMSCRIPTEN_NATIVE_OPTIMIZER='%installation_dir%/tools/optimizer_build/Release/optimizer%.exe%'",
+    "activated_cfg": "EMSCRIPTEN_ROOT='%installation_dir%';EMSCRIPTEN_NATIVE_OPTIMIZER='%installation_dir%/tools/optimizer_build/%cmake_build_type%optimizer%.exe%'",
     "activated_path": "%installation_dir%",
     "activated_env": "EMSCRIPTEN=%installation_dir%",
     "cmake_build_type": "Release",