diff --git a/knack/output.py b/knack/output.py
index 110f1e0..bbe3277 100644
--- a/knack/output.py
+++ b/knack/output.py
@@ -160,6 +160,8 @@ def out(self, obj, formatter=None, out_file=None):  # pylint: disable=no-self-us
             else:
                 raise
         except UnicodeEncodeError:
+            logger.warning("Unable to encode the output with %s encoding. Unsupported characters are discarded.",
+                           out_file.encoding)
             print(output.encode('ascii', 'ignore').decode('utf-8', 'ignore'),
                   file=out_file, end='')