diff --git a/suite/common/contentAreaUtils.js b/suite/common/contentAreaUtils.js
index d77585113b2b..6c5e42db8237 100644
--- a/suite/common/contentAreaUtils.js
+++ b/suite/common/contentAreaUtils.js
@@ -775,7 +775,7 @@ function getDefaultFileName(aDefaultFileName, aNameFromHeaders, aDocumentURI, aD
       var textToSubURI = Components.classes["@mozilla.org/intl/texttosuburi;1"]
                                    .getService(Components.interfaces.nsITextToSubURI);
       var charset = getCharsetforSave(aDocument);
-      return textToSubURI.unEscapeURIForUI(charset, url.fileName);
+      return validateFileName(textToSubURI.unEscapeURIForUI(charset, url.fileName));
     } catch (e) {
       // This is something like a wyciwyg:, data:, and so forth
       // URI... no usable filename here.