diff --git a/pyxtal/XRD.py b/pyxtal/XRD.py
index 3f072044..7b88306c 100644
--- a/pyxtal/XRD.py
+++ b/pyxtal/XRD.py
@@ -536,7 +536,7 @@ def plotly_pxrd(
             title="PXRD of " + self.name,
         )
 
-        if os.environ["_"].find("jupyter") == -1:
+        if os.environ.get("_", "").find("jupyter") == -1:
             if html is None:
                 return fig.to_html()
             else: