diff --git a/dtool/src/dtoolutil/filename.cxx b/dtool/src/dtoolutil/filename.cxx
index 7351a51e88..5008c4a97e 100644
--- a/dtool/src/dtoolutil/filename.cxx
+++ b/dtool/src/dtoolutil/filename.cxx
@@ -138,7 +138,7 @@ get_panda_root() {
       panda_root = "c:/cygwin";
     }
 
-    if (panda_root.empty() || panda_root[panda_root.length() - 1] != '\\') {
+    if (!panda_root.empty() || panda_root[panda_root.length() - 1] != '\\') {
       panda_root += '\\';
     }