diff --git a/.github/workflows/build-windows.yml b/.github/workflows/build-windows.yml
index aebad0e24cc1..e35f76a9f6b5 100644
--- a/.github/workflows/build-windows.yml
+++ b/.github/workflows/build-windows.yml
@@ -61,6 +61,7 @@ jobs:
       TILEDB_WEBP: ${{ matrix.TILEDB_WEBP }}
       TILEDB_CMAKE_BUILD_TYPE: 'Release'
       VCPKG_BINARY_SOURCES: 'clear;x-gha,readwrite'
+      CXXFLAGS: '/D_DISABLE_CONSTEXPR_MUTEX_CONSTRUCTOR' # https://github.com/actions/runner-images/issues/10004
     steps:
       - name: 'tiledb env prep'
         run: |
diff --git a/.github/workflows/unit-test-runs.yml b/.github/workflows/unit-test-runs.yml
index 0b1bfce01f39..baa5fb1762b0 100644
--- a/.github/workflows/unit-test-runs.yml
+++ b/.github/workflows/unit-test-runs.yml
@@ -10,7 +10,8 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [macos-latest, ubuntu-latest, windows-latest]
+        # Temporarily reverting to windows-2019 until https://github.com/actions/runner-images/issues/10004 gets fixed.
+        os: [macos-latest, ubuntu-latest, windows-2019]
       fail-fast: false
     name: Build - ${{ matrix.os }}
     timeout-minutes: 90
@@ -53,6 +54,11 @@ jobs:
         shell: bash
         if: ${{ !startsWith(matrix.os, 'windows-') }}
 
+      - name: 'Print env'
+        run: set
+        shell: cmd
+        if: ${{ startsWith(matrix.os, 'windows-') }}
+
       - name: 'Build standalone unit tests'
         run: |
           cmake -S . \
diff --git a/ports/triplets/x64-windows-asan.cmake b/ports/triplets/x64-windows-asan.cmake
index d19486d2cfed..2d1e356817c9 100644
--- a/ports/triplets/x64-windows-asan.cmake
+++ b/ports/triplets/x64-windows-asan.cmake
@@ -7,3 +7,7 @@ set(X_VCPKG_APPLOCAL_DEPS_INSTALL ON)
 # bigobj is needed for capnp.
 set(VCPKG_C_FLAGS "/fsanitize=address /bigobj")
 set(VCPKG_CXX_FLAGS "/fsanitize=address /bigobj")
+
+# https://github.com/actions/runner-images/issues/10004
+set(VCPKG_C_FLAGS "${VCPKG_C_FLAGS} /D_DISABLE_CONSTEXPR_MUTEX_CONSTRUCTOR")
+set(VCPKG_CXX_FLAGS "${VCPKG_CXX_FLAGS} /D_DISABLE_CONSTEXPR_MUTEX_CONSTRUCTOR")
diff --git a/ports/triplets/x64-windows.cmake b/ports/triplets/x64-windows.cmake
index c87b4f5dd385..eb54e7f5a55f 100644
--- a/ports/triplets/x64-windows.cmake
+++ b/ports/triplets/x64-windows.cmake
@@ -2,4 +2,8 @@ set(VCPKG_TARGET_ARCHITECTURE x64)
 set(VCPKG_CRT_LINKAGE dynamic)
 set(VCPKG_LIBRARY_LINKAGE static)
 
+# https://github.com/actions/runner-images/issues/10004
+set(VCPKG_C_FLAGS "/D_DISABLE_CONSTEXPR_MUTEX_CONSTRUCTOR")
+set(VCPKG_CXX_FLAGS "/D_DISABLE_CONSTEXPR_MUTEX_CONSTRUCTOR")
+
 set(X_VCPKG_APPLOCAL_DEPS_INSTALL ON)