diff --git a/ci/build.sh b/ci/build.sh
index f9f72be..5c415a2 100644
--- a/ci/build.sh
+++ b/ci/build.sh
@@ -1,40 +1,47 @@
-# osx unity build shell script
-
-# $1    UNITY_VERSION
-unityversion=$1
-
-editorpath="/Applications/Unity/Hub/Editor/$unityversion/Unity.app"
-
-# remove previous Editor.log
-editorlogpath="$HOME/Library/Logs/Unity/Editor.log"
-[ -f $editorlogpath ] && rm $editorlogpath
-
-echo "starting build using unity v$unityversion..."
-
-# launch unity in batch mode
-open -g $editorpath --args \
-    -batchmode \
-    -quit \
-    -nographics \
-    -executeMethod "Ktyl.Util.BuildCommand.Run" \
-    -logFile $editorlogpath \
-    -projectPath "$(pwd)/game"
-
-# wait for unity to exit
-while pgrep -x "Unity" > /dev/null
-do
-    sleep 1
-done
-
-
-if [ -f $editorlogpath ]; then
-    echo "build completed, dumping log"
-    cat $editorlogpath
-    echo "TODO: check result of build by looking at the last few lines"
-else
-    echo "no editor log to dump?"
-fi
-
-
-
-
+# osx unity build shell script
+
+# $1    UNITY_VERSION
+unityversion=$1
+
+editorlogpath="$HOME/Library/Logs/Unity/Editor.log"
+editorpath="/Applications/Unity/Hub/Editor/$unityversion/Unity.app"
+
+# find and kill existing unity instances
+if pgrep -x Unity
+then
+    echo "terminating existing unity processes..."
+    kill $(pgrep Unity)
+fi
+
+# remove previous Editor.log
+echo "removing previous editor log..."
+[ -f $editorlogpath ] && rm $editorlogpath
+
+echo "starting build using unity v$unityversion..."
+
+# launch unity in batch mode
+open -g $editorpath --args \
+    -batchmode \
+    -quit \
+    -nographics \
+    -executeMethod "Ktyl.Util.BuildCommand.Run" \
+    -logFile $editorlogpath \
+    -projectPath "$(pwd)/game"
+
+# wait for unity to exit
+while pgrep -x Unity > /dev/null
+do
+    sleep 1
+done
+
+if [ -f $editorlogpath ]; then
+    echo "build completed, dumping log"
+    cat $editorlogpath
+    echo "TODO: check result of build by looking at the last few lines"
+else
+    echo "no editor log to dump?"
+fi
+
+
+
+