diff --git a/win/build-deps.cmd b/win/build-deps.cmd
index 688a89f064..2f54a93aae 100644
--- a/win/build-deps.cmd
+++ b/win/build-deps.cmd
@@ -869,16 +869,13 @@ goto %NEXT_DEPENDENCY_LABEL%
 set DEPENDENCY_NAME=manifold
 set MANIFOLD_VERSION=3.2.1
 set DEPENDENCY_DIR=%DEPS_DIR%\manifold-%MANIFOLD_VERSION%
-set DEPENDENCY_INSTALL_DIR=%INSTALL_DIR%\manifold-%MANIFOLD_VERSION%
+set DEPENDENCY_INSTALL_NAME=manifold-%MANIFOLD_VERSION%
+set DEPENDENCY_INSTALL_DIR=%INSTALL_DIR%\%DEPENDENCY_INSTALL_NAME%
 set NEXT_DEPENDENCY_LABEL=Successful
-:: TODO: test whether manifold links the debug CRT for Debug builds and needs separate
-:: Release/Debug install dirs instead of sharing one.
 echo MANIFOLD_INSTALL_PATH=%DEPENDENCY_INSTALL_DIR%>>"%~dp0\%BUILD_DEPS_CACHE_PATH%"
 
-IF EXIST "%DEPENDENCY_INSTALL_DIR%" (
-    echo Found existing "%DEPENDENCY_INSTALL_DIR%", skipping
-    goto %NEXT_DEPENDENCY_LABEL%
-)
+call :CheckInstallation
+if %ERRORLEVEL%==200 GOTO %NEXT_DEPENDENCY_LABEL%
 
 call :GitCloneAndCheckoutRevision https://github.com/elalish/manifold.git "%DEPENDENCY_DIR%" v%MANIFOLD_VERSION%
 IF NOT %ERRORLEVEL%==0 GOTO :Error
@@ -893,12 +890,14 @@ call :RunCMake -DCMAKE_INSTALL_PREFIX="%DEPENDENCY_INSTALL_DIR%" ^
                -DMANIFOLD_CBIND=OFF ^
                -DMANIFOLD_TEST=OFF ^
                -DMANIFOLD_EXPORT=OFF ^
-               -DMANIFOLD_DOWNLOADS=OFF
+               -DMANIFOLD_DOWNLOADS=OFF ^
+               -DCMAKE_DEBUG_POSTFIX="_d"
 IF NOT %ERRORLEVEL%==0 GOTO :Error
 call :BuildCMakeProject "%DEPENDENCY_DIR%\%BUILD_DIR%" %BUILD_CFG%
 IF NOT %ERRORLEVEL%==0 GOTO :Error
 call :InstallCMakeProject "%DEPENDENCY_DIR%\%BUILD_DIR%" %BUILD_CFG%
 IF NOT %ERRORLEVEL%==0 GOTO :Error
+call :MarkInstallation
 goto %NEXT_DEPENDENCY_LABEL%
 
 :: :tbb
diff --git a/win/installers.py b/win/installers.py
index 8c8e8e153a..1e412cf5c4 100644
--- a/win/installers.py
+++ b/win/installers.py
@@ -1215,11 +1215,9 @@ def install_manifold(
     dependency_dir = deps_dir / f"{DEPENDENCY_NAME}-{MANIFOLD_VERSION}"
     dependency_install_dir = install_dir / f"{DEPENDENCY_NAME}-{MANIFOLD_VERSION}"
 
-    # TODO: test whether manifold links the debug CRT for Debug builds and needs separate
-    # Release/Debug install dirs instead of sharing one.
     build_deps_cache.add_entry("MANIFOLD_INSTALL_PATH", str(dependency_install_dir))
 
-    if is_already_installed(dependency_install_dir):
+    if is_already_installed(dependency_install_dir, expected_build_cfg=build_cfg):
         return
 
     git_clone_and_checkout_revision(
@@ -1244,8 +1242,10 @@ def install_manifold(
         "-DMANIFOLD_TEST=OFF",
         "-DMANIFOLD_EXPORT=OFF",
         "-DMANIFOLD_DOWNLOADS=OFF",
+        "-DCMAKE_DEBUG_POSTFIX=_d",
     )
 
     build_path = dependency_dir / vs_cfg_vars.build_dir
     build_cmake_project(DEPENDENCY_NAME, build_path, build_cfg, msbuild_multiproc)
     install_cmake_project(DEPENDENCY_NAME, build_path, build_cfg)
+    mark_installation(dependency_install_dir, build_cfg)