diff --git a/demos/python/start_env.sh b/demos/python/start_env.sh
index 498add5..95a0903 100755
--- a/demos/python/start_env.sh
+++ b/demos/python/start_env.sh
@@ -26,7 +26,9 @@ folder=jpype_env
 source $folder/bin/activate
 if [ $? -ne 0 ]; then
     echo "Virtual environment unable to be activated" >&2
-    return 3 # Need return instead of exit since we're running via source
+    # Try return first in case this script was sourced.
+    return 3 2>/dev/null
+    exit 3
 else
     echo "Python environment from $folder started and activated."
 fi
diff --git a/demos/python/start_jupyter_env.sh b/demos/python/start_jupyter_env.sh
index f902a9d..c30a279 100755
--- a/demos/python/start_jupyter_env.sh
+++ b/demos/python/start_jupyter_env.sh
@@ -20,9 +20,21 @@
 # Start the python environment (stored in folder $folder) with jpype1, numpy and others installed
 # and then launch jupyter
 
-source start_env.sh
+# Name of folder to use and python commands
+folder=jpype_env
 
-echo "Started virtual environment, now starting jupyter ..."
+# enter the environment
+source $folder/bin/activate
+
+if [[ "$VIRTUAL_ENV" != "" ]]
+then
+  echo "Started virtual environment, now starting jupyter ..."
+else
+  echo "Virtual environment not started, exiting"
+  # Try return first in case this script was sourced.
+  return 1 2>/dev/null
+  exit 1
+fi
 
 cd ../..
 jupyter notebook