--- a/mail/test/mozmill/content-tabs/test-about-support.js
+++ b/mail/test/mozmill/content-tabs/test-about-support.js
@@ -349,16 +349,17 @@ function test_send_via_email_public() {
 
   // Check that private data isn't in the output.
   if (check_text_in_body(contentBody, privateElem.textContent))
     mark_failure(["Found private data in compose window"]);
 
   close_compose_window(cwc);
   close_tab(tab);
 }
+test_send_via_email_public.EXCLUDED_PLATFORMS = ['linux'];  // See bug 1373809.
 
 /**
  * Test opening the compose window with private data.
  */
 function test_send_via_email_private() {
   let tab = open_about_support();
 
   // Display private data.
@@ -386,8 +387,9 @@ function test_send_via_email_private() {
 
   // Check that the warning text is in the output.
   if (!check_text_in_body(contentBody, warningText.get("text/html")))
     mark_failure(["Unable to find warning text in compose window"]);
 
   close_compose_window(cwc);
   close_tab(tab);
 }
+test_send_via_email_private.EXCLUDED_PLATFORMS = ['linux'];  // See bug 1373809.