diff --git a/Lib/idlelib/OutputWindow.py b/Lib/idlelib/OutputWindow.py
index 5a15873bae8..565cc9b772d 100644
--- a/Lib/idlelib/OutputWindow.py
+++ b/Lib/idlelib/OutputWindow.py
@@ -55,10 +55,12 @@ def flush(self):
     ]
 
     file_line_pats = [
+        # order of patterns matters
         r'file "([^"]*)", line (\d+)',
         r'([^\s]+)\((\d+)\)',
-        r'([^\s]+):\s*(\d+):',
-        r'^\s*(\S+.*?):\s*(\d+):',  # Win path with spaces, trim leading spaces
+        r'^(\s*\S.*?):\s*(\d+):',  # Win filename, maybe starting with spaces
+        r'([^\s]+):\s*(\d+):',     # filename or path, ltrim
+        r'^\s*(\S.*?):\s*(\d+):',  # Win abs path with embedded spaces, ltrim
     ]
 
     file_line_progs = None