diff --git a/mozilla/mailnews/compose/src/nsMsgCompose.cpp b/mozilla/mailnews/compose/src/nsMsgCompose.cpp
index 35865b29a11..dc931a854be 100644
--- a/mozilla/mailnews/compose/src/nsMsgCompose.cpp
+++ b/mozilla/mailnews/compose/src/nsMsgCompose.cpp
@@ -469,6 +469,11 @@ nsMsgCompose::ConvertAndLoadComposeWindow(nsString& aPrefix,
   TranslateLineEnding(aBuf);
   TranslateLineEnding(aSignature);
 
+  // this is probably a mapi send, so we need to replace '\n' with <br>
+  // so that the line breaks won't be lost by html.
+  if (!aQuoted && aHTMLEditor)
+    aBuf.ReplaceSubstring(NS_LITERAL_STRING("\n").get(), NS_LITERAL_STRING("<br>").get());
+
   // We're going to be inserting stuff, and MsgComposeCommands
   // may have set the editor to readonly in the recycled case.
   // So set it back to writable.