diff --git a/_distributions/macos.sh b/_distributions/macos.sh
index 9ce1e9d6166f2b67d2f06be05592731a5abb9e35..7439e1214d33e0b5e79f927634973291fcbf728c 100755
--- a/_distributions/macos.sh
+++ b/_distributions/macos.sh
@@ -3,5 +3,6 @@ set -ex
 packages="`cat package_list`"
 opam switch remove --yes 4.10.0 || true
 opam switch create 4.10.0
+eval $(opam env)
 _distributions/init_opam_switch.sh
 opam depext --install --yes $packages