diff --git a/modules/libpref/src/init/all.js b/modules/libpref/src/init/all.js
index d1afd2901d7750f8d8f40fa889e1d4ee028c99e8..1cdcf355c84603dd5dd194be23b46740fa8dd71f 100644
--- a/modules/libpref/src/init/all.js
+++ b/modules/libpref/src/init/all.js
@@ -2728,7 +2728,6 @@ pref("print.print_command", "lp -c -s ${MOZ_PRINTER_NAME:+-d\"$MOZ_PRINTER_NAME\
 
 // Login Manager prefs
 pref("signon.rememberSignons",              true);
-pref("signon.expireMasterPassword",         false);
 pref("signon.SignonFileName",               "signons.txt"); // obsolete 
 pref("signon.SignonFileName2",              "signons2.txt"); // obsolete
 pref("signon.SignonFileName3",              "signons3.txt"); // obsolete