Globally Unique Identifiers (GUIDs) are the primary key of all entities in CRM and are sequentially generated. There is often confusion about how GUIDs work, how unique they are, and how they are generated in CRM. It is an id of a record that is unique within that environment. That means it can be used to call a record in complete confidence that you will get the correct record.

1. GUIDs will always be unique.

2. GUIDs are generated sequentially in Dynamics CRM and are performant as a primary key.

3. There is no need to worry about duplicates.

4. Always keep the GUID of a record when moving between organizations or other systems.

5. It is best practice to maintain the GUID from any record when integrating or migrating between any environment. This will help to ensure data integrity, and there is no need for concern regarding GUID collision.