diff --git a/openmm-rbfe/OpenFE_showcase_1_RBFE_of_T4lysozyme.ipynb b/openmm-rbfe/OpenFE_showcase_1_RBFE_of_T4lysozyme.ipynb
index db71c8f..f28e8b9 100644
--- a/openmm-rbfe/OpenFE_showcase_1_RBFE_of_T4lysozyme.ipynb
+++ b/openmm-rbfe/OpenFE_showcase_1_RBFE_of_T4lysozyme.ipynb
@@ -1506,7 +1506,11 @@
    "cell_type": "code",
    "execution_count": 36,
    "id": "35bd3244",
-   "metadata": {},
+   "metadata": {
+    "tags": [
+     "nbval-skip"
+    ]
+   },
    "outputs": [],
    "source": [
     "# Get rid of the created netcdf checkpoint files\n",
@@ -1518,7 +1522,11 @@
    "cell_type": "code",
    "execution_count": 37,
    "id": "106ec948",
-   "metadata": {},
+   "metadata": {
+    "tags": [
+     "nbval-skip"
+    ]
+   },
    "outputs": [
     {
      "name": "stderr",
@@ -1584,7 +1592,11 @@
    "cell_type": "code",
    "execution_count": 38,
    "id": "820aaf86",
-   "metadata": {},
+   "metadata": {
+    "tags": [
+     "nbval-skip"
+    ]
+   },
    "outputs": [
     {
      "name": "stderr",
@@ -1667,7 +1679,11 @@
    "cell_type": "code",
    "execution_count": 39,
    "id": "fd1332db",
-   "metadata": {},
+   "metadata": {
+    "tags": [
+     "nbval-skip"
+    ]
+   },
    "outputs": [
     {
      "name": "stderr",