Simpler Format for User Email Addresses in Sandboxes

When you create or refresh a sandbox, Salesforce appends .invalid to all user email addresses. This email invalidation ensures that production users aren't sent automatically generated messages from the sandbox.

Where: This change applies to Lightning Experience and Salesforce Classic in Professional, Enterprise, Performance, and Unlimited editions.

How: Create a sandbox, and notice how user email addresses change. For example, the address becomes Previously, the address changed to