diff --git a/dtool/src/dtoolutil/filename.cxx b/dtool/src/dtoolutil/filename.cxx
index 6d37059f69..442f788249 100644
--- a/dtool/src/dtoolutil/filename.cxx
+++ b/dtool/src/dtoolutil/filename.cxx
@@ -1251,6 +1251,7 @@ scan_directory(vector_string &contents) const {
     return false;
   }
 
+  errno = 0;
   struct dirent *d;
   d = readdir(root);
   while (d != (struct dirent *)NULL) {