diff --git a/bob/devtools/data/conda_build_config.yaml b/bob/devtools/data/conda_build_config.yaml
index 687b561798906a48cbf9af5afbde41ef7df392ae..62550979f381f5231e4c27cdcbebeb0f9fcbd960 100644
--- a/bob/devtools/data/conda_build_config.yaml
+++ b/bob/devtools/data/conda_build_config.yaml
@@ -87,6 +87,12 @@ rust_compiler:
 rust_compiler_version:
   - 1.40.0
 
+CONDA_BUILD_SYSROOT:            # [osx]
+  - /opt/MacOSX10.10.sdk        # [osx]
+# This helps CMAKE find the sysroot. See
+# https://cmake.org/cmake/help/v3.11/variable/CMAKE_OSX_SYSROOT.html
+SDKROOT:                        # [osx]
+  - /opt/MacOSX10.10.sdk        # [osx]
 macos_machine:                 # [osx]
   - x86_64-apple-darwin13.4.0  # [osx and x86_64]
   - arm64-apple-darwin20.0.0   # [osx and arm64]