diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index e2da025421d..99e79447b83 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -1,82 +1,87 @@
 name: coverage-linux
-on:
-  push:
-    branches:
-      - main
-  pull_request:
-jobs:
-  build:
-    name: ${{ matrix.name }}
-    runs-on: ubuntu-latest
 
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - name: flambda2_coverage
-            config: --enable-middle-end=flambda2 --enable-coverage
-            ocamlparam: ''
+# CR mshinwell: fix build and re-enable.  Something needs to be done
+# about a duplicate unix.cmxa argument to ocamlopt.
 
-    env:
-      J: "3"
-
-    steps:
-    - name: Checkout the Flambda backend repo
-      uses: actions/checkout@master
-      with:
-        path: 'flambda_backend'
-
-    # This adds a switch at $GITHUB_WORKSPACE/_opam
-    - name: Set up OCaml 4.14
-      uses: ocaml/setup-ocaml@v2
-      with:
-        ocaml-compiler: 4.14
-        opam-pin: false
-        opam-depext: false
-
-    - name: Get host build environment from cache
-      uses: actions/cache@v1
-      id: cache
-      with:
-        path: ${{ github.workspace }}/_opam
-        key: ${{ matrix.os }}-cache-ocaml-414-dune-2.9.1-g7606d586-menhir20210419
-
-    - name: Install menhir
-      if: steps.cache.outputs.cache-hit != 'true'
-      run: |
-        opam pin menhir 20210419
-
-    - name: Build bisect_ppx
-      if: steps.cache.outputs.cache-hit != 'true'
-      run: |
-        opam pin ppxlib 0.25.1
-        opam pin bisect_ppx --yes \
-          git+https://github.com/lukemaurer/bisect_ppx#html-report-collate-fix
-
-    - name: Trim cached files
-      if: steps.cache.outputs.cache-hit != 'true'
-      run: |
-        # Remove unneeded parts to shrink cache file
-        rm -rf _opam/{lib/ocaml/expunge,bin/*.byte}
-
-    - name: Configure Flambda backend
-      working-directory: flambda_backend
-      run: |
-        autoconf
-        ./configure \
-          --prefix=$GITHUB_WORKSPACE/_install \
-          --with-dune=$GITHUB_WORKSPACE/_opam/bin/dune \
-          ${{ matrix.config }}
-
-
-    - name: Build, install and test Flambda backend
-      working-directory: flambda_backend
-      run: opam exec -- make ci
-      env:
-        BUILD_OCAMLPARAM: ${{ matrix.ocamlparam }}
-
-    - name: Publish coverage report
-      uses: actions/upload-artifact@v3
-      with:
-        name: coverage
-        path: flambda_backend/_coverage/**
+# on:
+#   push:
+#     branches:
+#       - main
+#   pull_request:
+# jobs:
+#   build:
+#     name: ${{ matrix.name }}
+#     runs-on: ubuntu-latest
+#
+#     strategy:
+#       fail-fast: false
+#       matrix:
+#         include:
+#           - name: flambda2_coverage
+#             config: --enable-middle-end=flambda2 --enable-coverage
+#             ocamlparam: ''
+#
+#     env:
+#       J: "3"
+#
+#     steps:
+#     - name: Checkout the Flambda backend repo
+#       uses: actions/checkout@master
+#       with:
+#         path: 'flambda_backend'
+#
+#     # This adds a switch at $GITHUB_WORKSPACE/_opam
+#     - name: Set up OCaml 4.14
+#       uses: ocaml/setup-ocaml@v2
+#       with:
+#         ocaml-compiler: 4.14
+#         opam-pin: false
+#         opam-depext: false
+#
+#     - name: Get host build environment from cache
+#       uses: actions/cache@v1
+#       id: cache
+#       with:
+#         path: ${{ github.workspace }}/_opam
+#         key: ${{ matrix.os }}-cache-ocaml-414-dune-2.9.1-g7606d586-menhir20210419
+#
+#     - name: Install menhir
+#       if: steps.cache.outputs.cache-hit != 'true'
+#       run: |
+#         opam pin menhir 20210419
+#
+#     - name: Build bisect_ppx
+#       if: steps.cache.outputs.cache-hit != 'true'
+#       run: |
+#         opam pin ppxlib 0.25.1
+#         opam pin bisect_ppx --yes \
+#           git+https://github.com/lukemaurer/bisect_ppx#html-report-collate-fix
+#
+#     - name: Trim cached files
+#       if: steps.cache.outputs.cache-hit != 'true'
+#       run: |
+#         # Remove unneeded parts to shrink cache file
+#         rm -rf _opam/{lib/ocaml/expunge,bin/*.byte}
+#
+#     - name: Configure Flambda backend
+#       working-directory: flambda_backend
+#       run: |
+#         autoconf
+#         ./configure \
+#           --prefix=$GITHUB_WORKSPACE/_install \
+#           --with-dune=$GITHUB_WORKSPACE/_opam/bin/dune \
+#           ${{ matrix.config }}
+#
+#
+#     - name: Build, install and test Flambda backend
+#       working-directory: flambda_backend
+#       run: opam exec -- make ci
+#       env:
+#         BUILD_OCAMLPARAM: ${{ matrix.ocamlparam }}
+#
+#     - name: Publish coverage report
+#       uses: actions/upload-artifact@v3
+#       with:
+#         name: coverage
+#         path: flambda_backend/_coverage/**
+#