diff --git a/electrum/gui/qt/seed_dialog.py b/electrum/gui/qt/seed_dialog.py
index 1006dfd90..86fc15ec9 100644
--- a/electrum/gui/qt/seed_dialog.py
+++ b/electrum/gui/qt/seed_dialog.py
@@ -207,5 +207,6 @@ class SeedDialog(WindowModalDialog):
         title =  _("Your wallet generation seed is:")
         slayout = SeedLayout(title=title, seed=seed, msg=True, passphrase=passphrase)
         vbox.addLayout(slayout)
-        run_hook('set_seed', seed, slayout.seed_e)
+        has_extension = True if passphrase else False
+        run_hook('set_seed', seed, has_extension, slayout.seed_e)
         vbox.addLayout(Buttons(CloseButton(self)))
diff --git a/electrum/plugins/revealer/qt.py b/electrum/plugins/revealer/qt.py
index 0ce605622..69c9fcd32 100644
--- a/electrum/plugins/revealer/qt.py
+++ b/electrum/plugins/revealer/qt.py
@@ -57,8 +57,9 @@ class Plugin(BasePlugin):
         make_dir(self.base_dir)
 
     @hook
-    def set_seed(self, seed, parent):
+    def set_seed(self, seed, has_extension, parent):
         self.cseed = seed.upper()
+        self.has_extension = has_extension
         parent.addButton(':icons/revealer.png', partial(self.setup_dialog, parent), "Revealer"+_(" secret backup utility"))
 
     def requires_settings(self):
@@ -168,6 +169,10 @@ class Plugin(BasePlugin):
                                      "<br/>","<b>", self.base_dir+ self.filename+self.version+"_"+self.code_id,"</b>"]))
         dialog.close()
 
+    def ext_warning(self, dialog):
+        dialog.show_message(''.join(["<b>",_("Warning: "), "</b>", _("your seed extension will not be included in the encrypted backup.")]))
+        dialog.close()
+
     def bdone(self, dialog):
         dialog.show_message(''.join([_("Digital Revealer ({}_{}) saved as PNG and PDF at:").format(self.version, self.code_id),
                                      "<br/>","<b>", self.base_dir + 'revealer_' +self.version + '_'+ self.code_id, '</b>']))
@@ -360,6 +365,9 @@ class Plugin(BasePlugin):
             self.filename = self.wallet_name+'_'+ _('seed')+'_'
             self.was = self.wallet_name +' ' + _('seed')
 
+        if self.has_extension:
+            self.ext_warning(self.c_dialog)
+
         if not calibration:
             self.toPdf(QImage(cypherseed))
             QDesktopServices.openUrl (QUrl.fromLocalFile(os.path.abspath(self.base_dir+self.filename+self.version+'_'+self.code_id+'.pdf')))