The error is caused by the user.user_info.save() line has thrownthrowing an errorexception, and the transaction has beenwas flagged as broken (PostgreSQL enforces rolling back either the whole transaction, or to any savepoint stored before doing any more queries in theinside that transaction).
You can rollback the transaction when an error occurs like so:
from django.db import IntegrityError, transaction @receiver(post_save, sender=User) def saveUserAndInfo(sender, instance, **kwargs): user = instance try: with transaction.atomic(): user.user_info.save() except IntegrityError: info = UserInfo() info.user = user info.save() This is greatly described in the documentation.
Also, note that catching all exception types is not generally the best idea as you might silence exceptions you weren't expecting.