diff --git a/makepanda/makepandacore.py b/makepanda/makepandacore.py
index 093fcd3f17..85796a9430 100644
--- a/makepanda/makepandacore.py
+++ b/makepanda/makepandacore.py
@@ -1492,6 +1492,8 @@ def SdkLocateSpeedTree():
     # thirdparty dir, and pick the highest-numbered one.
     speedtrees = []
     dir = GetThirdpartyDir()
+    if not os.path.exists(dir):
+        return
     for dirname in os.listdir(dir):
         if dirname.startswith('SpeedTree SDK v'):
             version = dirname[15:].split()[0]