diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 87261b7..a09099d 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -17,7 +17,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: windows-latest
+    runs-on: windows-2025
 
     steps:
       - name: Checkout repository
@@ -26,10 +26,16 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: '3.11'
+          python-version: '3.11.9'
 
-      - name: Install PyInstaller
-        run: pip install pyinstaller
+      - name: Install pinned build toolchain
+        run: python -m pip install --disable-pip-version-check -r requirements-build.txt
+
+      - name: Verify build toolchain
+        run: |
+          python --version
+          pyinstaller --version
+          python -m pip show pyinstaller pyinstaller-hooks-contrib
 
       - name: Syntax check
         run: python -m py_compile setup_tool.py setup_tool_dynamic.py remote_packages.py tests/test_safety.py