fix 2fa wallet creation via qt gui

closes #5334

electrum/base_wizard.py

@@ -560,11 +560,13 @@ class BaseWizard(Logger):
         self.terminate()
 
     def create_storage(self, path):
+        if os.path.exists(path):
+            raise Exception('file already exists at path')
         if not self.pw_args:
             return
         password, encrypt_storage, storage_enc_version = self.pw_args
         storage = WalletStorage(path)
-        storage.set_keystore_encryption(bool(password))  # and encrypt_keystore)
+        storage.set_keystore_encryption(bool(password))
         if encrypt_storage:
             storage.set_password(password, enc_version=storage_enc_version)
         for key, value in self.data.items():

electrum/plugins/trustedcoin/qt.py

@@ -43,6 +43,7 @@ from electrum.i18n import _
 from electrum.plugin import hook
 from electrum.util import is_valid_email
 from electrum.logging import Logger
+from electrum.base_wizard import GoBack
 
 from .trustedcoin import TrustedCoinPlugin, server
 
@@ -221,9 +222,13 @@ class Plugin(TrustedCoinPlugin):
             _('If you are online, click on "{}" to continue.').format(_('Next'))
         ]
         msg = '\n\n'.join(msg)
-        wizard.create_storage(wizard.path)
         wizard.reset_stack()
-        wizard.confirm_dialog(title='', message=msg, run_next = lambda x: wizard.run('accept_terms_of_use'))
+        try:
+            wizard.confirm_dialog(title='', message=msg, run_next = lambda x: wizard.run('accept_terms_of_use'))
+        except GoBack:
+            # user clicked 'Cancel' and decided to move wallet file manually
+            wizard.create_storage(wizard.path)
+            raise
 
     def accept_terms_of_use(self, window):
         vbox = QVBoxLayout()