you are right. The database creation breaks at assigning the main company to the main partner. Similarly, in an existing database you cannot create a new partner without a company, then edit the user and assign a company to it. It will lead to the same error, "You can not change the company as the partner/user has mutiple user linked with different companies.". Seems easy to fix by checking if the partner is associated with any users at all.
Willem,
you are right. The database creation breaks at assigning the main company to the main partner. Similarly, in an existing database you cannot create a new partner without a company, then edit the user and assign a company to it. It will lead to the same error, "You can not change the company as the partner/user has mutiple user linked with different companies.". Seems easy to fix by checking if the partner is associated with any users at all.