diff --git a/Lib/idlelib/GrepDialog.py b/Lib/idlelib/GrepDialog.py
index 01e0483..27fcc33 100644
--- a/Lib/idlelib/GrepDialog.py
+++ b/Lib/idlelib/GrepDialog.py
@@ -81,7 +81,7 @@
         hits = 0
         for fn in list:
             try:
-                f = open(fn)
+                f = open(fn, errors='replace')
             except IOError as msg:
                 print(msg)
                 continue