diff --git a/aider/io.py b/aider/io.py
index 086813b61..dee90b78f 100644
--- a/aider/io.py
+++ b/aider/io.py
@@ -148,6 +148,7 @@ class InputOutput:
             return
         except UnicodeError as e:
             self.tool_error(f"{filename}: {e}")
+            self.tool_error("Use --encoding to set the unicode encoding.")
             return
 
     def write_text(self, filename, content):