diff --git a/gui/qt/__init__.py b/gui/qt/__init__.py
index d5d2b061..ea1f6b78 100644
--- a/gui/qt/__init__.py
+++ b/gui/qt/__init__.py
@@ -163,7 +163,12 @@ class ElectrumGui:
         if action is not None:
             import installwizard
             wizard = installwizard.InstallWizard(self.config, self.network, storage)
-            wallet = wizard.run(action)
+            try:
+                wallet = wizard.run(action)
+            except BaseException as e:
+                traceback.print_exc(file=sys.stdout)
+                QMessageBox.information(None, _('Error'), str(e), _('OK'))
+                return
             if not wallet:
                 return
         else:
diff --git a/gui/qt/installwizard.py b/gui/qt/installwizard.py
index 85259684..46f954ae 100644
--- a/gui/qt/installwizard.py
+++ b/gui/qt/installwizard.py
@@ -389,13 +389,7 @@ class InstallWizard(QDialog):
                 wallet.add_master_public_key("x3/", xpub3)
 
             elif action == 'create_accounts':
-                try:
-                    wallet.create_main_account(password)
-                except BaseException as e:
-                    import traceback
-                    traceback.print_exc(file=sys.stdout)
-                    QMessageBox.information(None, _('Error'), str(e), _('OK'))
-                    return
+                wallet.create_main_account(password)
                 self.waiting_dialog(wallet.synchronize)
 
             else:
diff --git a/lib/wallet.py b/lib/wallet.py
index cea0a2e0..fe3128c6 100644
--- a/lib/wallet.py
+++ b/lib/wallet.py
@@ -1296,6 +1296,8 @@ class BIP32_Wallet(Deterministic_Wallet):
             raise InvalidPassword()
 
     def add_master_public_key(self, name, xpub):
+        if xpub in self.master_public_keys.values():
+            raise BaseException('Duplicate master public key')
         self.master_public_keys[name] = xpub
         self.storage.put('master_public_keys', self.master_public_keys, True)