diff --git a/master.cfg b/master.cfg
index a137c49..49ba5c1 100644
--- a/master.cfg
+++ b/master.cfg
@@ -480,13 +480,15 @@ send to the gdb-testers mailing list."""
         # There is no build breakage anymore!  Yay!  Now, let's see if
         # we need to clean up any lock file from previous breaks.
         lockfile = make_breakage_lockfile_name (branch, name)
-        with open (lockfile, 'r') as f:
-            rev_broke = f.readline ().lstrip ("Commit: ")
-        mid_file = make_breakage_root_message_id_filename (rev_broke, branch)
+        rev_broke = None
+        mid_file = None
         if os.path.exists (lockfile):
+            with open (lockfile, 'r') as f:
+                rev_broke = f.readline ().lstrip ("Commit: ")
+            mid_file = make_breakage_root_message_id_filename (rev_broke, branch)
             # We need to clean the lockfile.  Garbage-collect it here.
             os.remove (lockfile)
-        if os.path.exists (mid_file):
+        if mid_file and os.path.exists (mid_file):
             # Garbage-collect the Message-Id file
             os.remove (mid_file)