diff --git a/.github/workflows/build_check.yml b/.github/workflows/build_check.yml
index 64a6858b6..56dd1b806 100644
--- a/.github/workflows/build_check.yml
+++ b/.github/workflows/build_check.yml
@@ -50,7 +50,7 @@ jobs:
         DISPLAY: test
     - name: Install Sphinx prereq
       run: |
-        conda install -c main conda-mamba-solver libmamba libarchive
+        conda install -c main --force-reinstall --solver classic conda-mamba-solver libmamba libarchive
         conda install -c conda-forge sphinx sphinx_rtd_theme nbconvert pandoc ipython ipython_genutils
     - name: Run the docs
       run: |