diff --git a/scripts/prepare_env.sh b/scripts/prepare_env.sh
index b8eb789d7..ec94120dd 100755
--- a/scripts/prepare_env.sh
+++ b/scripts/prepare_env.sh
@@ -9,5 +9,6 @@ set -ex
 # GNU command line tools
 brew install coreutils
 
-brew install pyyaml
-pip3 install pyyaml || true
+python3 -m venv .venv
+source .venv/bin/activate
+pip3 install pyyaml