diff --git a/.github/workflows/build-pull-request.yml b/.github/workflows/build-pull-request.yml
index bc0d2d625a..216fb995e1 100644
--- a/.github/workflows/build-pull-request.yml
+++ b/.github/workflows/build-pull-request.yml
@@ -38,132 +38,146 @@ jobs:
         uses: actions/checkout@v4
       - name: Build and Test (cmake)
         uses: ./.github/actions/build_cmake
-  linux-x86_64-AVX2-cmake:
-    name: Linux x86_64 AVX2 (cmake)
-    needs: linux-x86_64-cmake
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Build and Test (cmake)
-        uses: ./.github/actions/build_cmake
-        with:
-          opt_level: avx2
-  linux-x86_64-AVX512-cmake:
-    name: Linux x86_64 AVX512 (cmake)
-    needs: linux-x86_64-cmake
-    runs-on: faiss-aws-m7i.large
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Build and Test (cmake)
-        uses: ./.github/actions/build_cmake
-        with:
-          opt_level: avx512
-  linux-x86_64-AVX512_SPR-cmake:
-    name: Linux x86_64 AVX512_SPR (cmake)
-    needs: linux-x86_64-cmake
-    runs-on: faiss-aws-m7i.large
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Build and Test (cmake)
-        uses: ./.github/actions/build_cmake
-        with:
-          opt_level: avx512_spr
-  linux-x86_64-GPU-cmake:
-    name: Linux x86_64 GPU (cmake)
-    needs: linux-x86_64-cmake
-    runs-on: 4-core-ubuntu-gpu-t4
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Build and Test (cmake)
-        uses: ./.github/actions/build_cmake
-        with:
-          gpu: ON
-  linux-x86_64-GPU-w-CUVS-cmake:
-    name: Linux x86_64 GPU w/ cuVS (cmake)
-    needs: linux-x86_64-cmake
-    runs-on: 4-core-ubuntu-gpu-t4
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Build and Test (cmake)
-        uses: ./.github/actions/build_cmake
-        with:
-          gpu: ON
-          cuvs: ON
-  linux-x86_64-GPU-w-ROCm-cmake:
-    name: Linux x86_64 GPU w/ ROCm (cmake)
-    needs: linux-x86_64-cmake
-    runs-on: faiss-amd-MI200
-    container:
-      image: ubuntu:22.04
-      options: --device=/dev/kfd --device=/dev/dri --ipc=host --shm-size 16G --group-add video --cap-add=SYS_PTRACE --cap-add=SYS_ADMIN
-    steps:
-      - name: Container setup
-        run: |
-            if [ -f /.dockerenv ]; then
-              apt-get update && apt-get install -y sudo && apt-get install -y git
-              git config --global --add safe.directory '*'
-            else
-              echo 'Skipping. Current job is not running inside a container.'
-            fi
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Build and Test (cmake)
-        uses: ./.github/actions/build_cmake
-        with:
-          gpu: ON
-          rocm: ON
-  linux-arm64-SVE-cmake:
-    name: Linux arm64 SVE (cmake)
-    needs: linux-x86_64-cmake
-    runs-on: faiss-aws-r8g.large
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Build and Test (cmake)
-        uses: ./.github/actions/build_cmake
-        with:
-          opt_level: sve
-        env:
-          # Context: https://github.com/facebookresearch/faiss/wiki/Troubleshooting#surprising-faiss-openmp-and-openblas-interaction
-          OPENBLAS_NUM_THREADS: '1'
-  linux-x86_64-conda:
-    name: Linux x86_64 (conda)
-    needs: linux-x86_64-cmake
-    runs-on: ubuntu-latest
+  osx-arm64-nightly:
+    name: OSX arm64 nightlies
+    runs-on: macos-14
     steps:
       - name: Checkout
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
           fetch-tags: true
-      - name: Build and Package (conda)
-        uses: ./.github/actions/build_conda
-  windows-x86_64-conda:
-    name: Windows x86_64 (conda)
-    needs: linux-x86_64-cmake
-    runs-on: windows-2019
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-        with:
-          fetch-depth: 0
-          fetch-tags: true
-      - name: Build and Package (conda)
-        uses: ./.github/actions/build_conda
-  linux-arm64-conda:
-    name: Linux arm64 (conda)
-    needs: linux-x86_64-cmake
-    runs-on: 2-core-ubuntu-arm
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
+      - uses: ./.github/actions/build_conda
+        env:
+          ANACONDA_API_TOKEN: ${{ secrets.ANACONDA_API_TOKEN }}
         with:
-          fetch-depth: 0
-          fetch-tags: true
-      - name: Build and Package (conda)
-        uses: ./.github/actions/build_conda
+          label: nightly
+  # linux-x86_64-AVX2-cmake:
+  #   name: Linux x86_64 AVX2 (cmake)
+  #   needs: linux-x86_64-cmake
+  #   runs-on: ubuntu-latest
+  #   steps:
+  #     - name: Checkout
+  #       uses: actions/checkout@v4
+  #     - name: Build and Test (cmake)
+  #       uses: ./.github/actions/build_cmake
+  #       with:
+  #         opt_level: avx2
+  # linux-x86_64-AVX512-cmake:
+  #   name: Linux x86_64 AVX512 (cmake)
+  #   needs: linux-x86_64-cmake
+  #   runs-on: faiss-aws-m7i.large
+  #   steps:
+  #     - name: Checkout
+  #       uses: actions/checkout@v4
+  #     - name: Build and Test (cmake)
+  #       uses: ./.github/actions/build_cmake
+  #       with:
+  #         opt_level: avx512
+  # linux-x86_64-AVX512_SPR-cmake:
+  #   name: Linux x86_64 AVX512_SPR (cmake)
+  #   needs: linux-x86_64-cmake
+  #   runs-on: faiss-aws-m7i.large
+  #   steps:
+  #     - name: Checkout
+  #       uses: actions/checkout@v4
+  #     - name: Build and Test (cmake)
+  #       uses: ./.github/actions/build_cmake
+  #       with:
+  #         opt_level: avx512_spr
+  # linux-x86_64-GPU-cmake:
+  #   name: Linux x86_64 GPU (cmake)
+  #   needs: linux-x86_64-cmake
+  #   runs-on: 4-core-ubuntu-gpu-t4
+  #   steps:
+  #     - name: Checkout
+  #       uses: actions/checkout@v4
+  #     - name: Build and Test (cmake)
+  #       uses: ./.github/actions/build_cmake
+  #       with:
+  #         gpu: ON
+  # linux-x86_64-GPU-w-CUVS-cmake:
+  #   name: Linux x86_64 GPU w/ cuVS (cmake)
+  #   needs: linux-x86_64-cmake
+  #   runs-on: 4-core-ubuntu-gpu-t4
+  #   steps:
+  #     - name: Checkout
+  #       uses: actions/checkout@v4
+  #     - name: Build and Test (cmake)
+  #       uses: ./.github/actions/build_cmake
+  #       with:
+  #         gpu: ON
+  #         cuvs: ON
+  # linux-x86_64-GPU-w-ROCm-cmake:
+  #   name: Linux x86_64 GPU w/ ROCm (cmake)
+  #   needs: linux-x86_64-cmake
+  #   runs-on: faiss-amd-MI200
+  #   container:
+  #     image: ubuntu:22.04
+  #     options: --device=/dev/kfd --device=/dev/dri --ipc=host --shm-size 16G --group-add video --cap-add=SYS_PTRACE --cap-add=SYS_ADMIN
+  #   steps:
+  #     - name: Container setup
+  #       run: |
+  #           if [ -f /.dockerenv ]; then
+  #             apt-get update && apt-get install -y sudo && apt-get install -y git
+  #             git config --global --add safe.directory '*'
+  #           else
+  #             echo 'Skipping. Current job is not running inside a container.'
+  #           fi
+  #     - name: Checkout
+  #       uses: actions/checkout@v4
+  #     - name: Build and Test (cmake)
+  #       uses: ./.github/actions/build_cmake
+  #       with:
+  #         gpu: ON
+  #         rocm: ON
+  # linux-arm64-SVE-cmake:
+  #   name: Linux arm64 SVE (cmake)
+  #   needs: linux-x86_64-cmake
+  #   runs-on: faiss-aws-r8g.large
+  #   steps:
+  #     - name: Checkout
+  #       uses: actions/checkout@v4
+  #     - name: Build and Test (cmake)
+  #       uses: ./.github/actions/build_cmake
+  #       with:
+  #         opt_level: sve
+  #       env:
+  #         # Context: https://github.com/facebookresearch/faiss/wiki/Troubleshooting#surprising-faiss-openmp-and-openblas-interaction
+  #         OPENBLAS_NUM_THREADS: '1'
+  # linux-x86_64-conda:
+  #   name: Linux x86_64 (conda)
+  #   needs: linux-x86_64-cmake
+  #   runs-on: ubuntu-latest
+  #   steps:
+  #     - name: Checkout
+  #       uses: actions/checkout@v4
+  #       with:
+  #         fetch-depth: 0
+  #         fetch-tags: true
+  #     - name: Build and Package (conda)
+  #       uses: ./.github/actions/build_conda
+  # windows-x86_64-conda:
+  #   name: Windows x86_64 (conda)
+  #   needs: linux-x86_64-cmake
+  #   runs-on: windows-2019
+  #   steps:
+  #     - name: Checkout
+  #       uses: actions/checkout@v4
+  #       with:
+  #         fetch-depth: 0
+  #         fetch-tags: true
+  #     - name: Build and Package (conda)
+  #       uses: ./.github/actions/build_conda
+  # linux-arm64-conda:
+  #   name: Linux arm64 (conda)
+  #   needs: linux-x86_64-cmake
+  #   runs-on: 2-core-ubuntu-arm
+  #   steps:
+  #     - name: Checkout
+  #       uses: actions/checkout@v4
+  #       with:
+  #         fetch-depth: 0
+  #         fetch-tags: true
+  #     - name: Build and Package (conda)
+  #       uses: ./.github/actions/build_conda
diff --git a/faiss/impl/mapped_io.cpp b/faiss/impl/mapped_io.cpp
index 84ccd4c44f..32486a9e6d 100644
--- a/faiss/impl/mapped_io.cpp
+++ b/faiss/impl/mapped_io.cpp
@@ -227,12 +227,15 @@ struct MmappedFileMappingOwner::PImpl {
 #else
 
 struct MmappedFileMappingOwner::PImpl {
-    PImpl(FILE* f) {
-        FAISS_THROW_FMT("Not implemented");
+    void* ptr = nullptr;
+    size_t ptr_size = 0;
+
+    PImpl(const std::string& filename) {
+        FAISS_THROW_MSG("Not implemented");
     }
 
-    ~PImpl() {
-        FAISS_THROW_FMT("Not implemented");
+    PImpl(FILE* f) {
+        FAISS_THROW_MSG("Not implemented");
     }
 };
 
diff --git a/tests/test_io.py b/tests/test_io.py
index 9e1853cb49..e2c5e69a18 100644
--- a/tests/test_io.py
+++ b/tests/test_io.py
@@ -11,6 +11,7 @@
 import io
 import sys
 import pickle
+import platform
 from multiprocessing.pool import ThreadPool
 from common_faiss_tests import get_dataset_2
 
@@ -485,6 +486,10 @@ def test_reader(self):
 
 
 class TestIOFlatMMap(unittest.TestCase):
+    @unittest.skipIf(
+        platform.system() not in ["Windows", "Linux"],
+        "supported OSes only"
+    )
     def test_mmap(self): 
         xt, xb, xq = get_dataset_2(32, 0, 100, 50)
         index = faiss.index_factory(32, "SQfp16", faiss.METRIC_L2)