Currently, when a user creates a new deal, and lookup the related Account on the create page, if the Account does not exist, it automatically creates a new account. 

However, this bypasses all the validation rules of creating a new Account. 

I would like to prevent this "functionality" so that the deal can only be linked to an already existing Account. If the Account does not exist, the user would have to manually first create the Account and then add the deal against it.

Please advise how I can do this. Thanks.