diff --git a/eeschema/sch_validators.cpp b/eeschema/sch_validators.cpp
index 2103e79986..fc3b8e0977 100644
--- a/eeschema/sch_validators.cpp
+++ b/eeschema/sch_validators.cpp
@@ -113,7 +113,7 @@ bool SCH_FIELD_VALIDATOR::Validate( wxWindow* aParent )
                 else if( excludeChar == ' ' )
                     badCharsFound.Add( _( "space" ) );
                 else
-                    badCharsFound.Add( wxString::Format( wxT( "'%s'" ), excludeChar ) );
+                    badCharsFound.Add( wxString::Format( wxT( "'%c'" ), excludeChar ) );
             }
         }
 #else