User ID (a.k.a. Member ID)

Each time a new contact added into the database, they are automatically assigned a unique number called User ID (a.k.a. Member ID). All other fields in the contact record (like email, first name, address etc.) can be changed, but this system generated user ID will always remain the same until the record is deleted. 

Both the contact and administrators can view this ID:

Admin view

Contact View

Import Considerations

• The user ID field is exported each time you export your contact/member records, see Exporting members and other contacts
• When importing existing records (e.g. when you do a bulk update) the system will use the User ID (or email) to uniquely identify the record. If the system recognizes the imported record by either User ID or Email that record will be updated with the new imported information, otherwise a new record is created. See also Import Field Guide
• Do not attempt to modify this User ID via import, your changes will not take or worse you may end up updating the wrong record (if you somehow specify a valid existing user ID)