I think that colon doesn't fit there, there's no text after that colon ':' or code to be shown as variable '%s' after it.
if not tx_dict["complete"]:
assert "input_info" in tx_dict.keys()
except:
- QMessageBox.critical(None, "Unable to parse transaction", _("Electrum was unable to parse your transaction:"))
+ QMessageBox.critical(None, "Unable to parse transaction", _("Electrum was unable to parse your transaction"))
return None
return tx_dict