diff --git a/trac/mimeview/api.py b/trac/mimeview/api.py
--- a/trac/mimeview/api.py
+++ b/trac/mimeview/api.py
@@ -834,7 +834,8 @@
                                                          content, selector)
         req.send_response(200)
         req.send_header('Content-Type', output_type)
-        req.send_header('Content-Disposition', 'filename=%s.%s' % 
+        if filename:
+            req.send_header('Content-Disposition', 'filename=%s.%s' % 
                         (filename, ext))
         req.end_headers()
         req.write(content)
diff --git a/trac/ticket/query.py b/trac/ticket/query.py
--- a/trac/ticket/query.py
+++ b/trac/ticket/query.py
@@ -800,7 +800,7 @@
 
         if format:
             Mimeview(self.env).send_converted(req, 'trac.ticket.Query', query,
-                                              format, 'query')
+                                              format, filename='')
 
         return self.display_html(req, query)
 
diff --git a/trac/ticket/web_ui.py b/trac/ticket/web_ui.py
--- a/trac/ticket/web_ui.py
+++ b/trac/ticket/web_ui.py
@@ -525,7 +525,7 @@
         if format:
             # FIXME: mime.send_converted(context, ticket, 'ticket_x')
             mime.send_converted(req, 'trac.ticket.Ticket', ticket,
-                                format, 'ticket_%d' % ticket.id)
+                                format, filename='')
 
         def add_ticket_link(css_class, id):
             t = ticket.resource(id=id, version=None)