There are a few approaches you can take here, which I will list in order of preference. These should work just about anywhere merge fields can be used. ___ **Create a Custom Permission** You can check if someone has a `Custom Permission` in a formula as follows: $Permission.My_Custom_Permission__c Steps: 1. Create `Custom Permission` 2. Add it to a `Permission Set` 3. Assign that `Permission Set` to any `User` you wish to exempt from validation --- **Hierarchy Custom Setting** If you don't find the above palatable for some reason, you can also check a `Hierarchy Custom Setting` in a formula as follows: $My_Hierarchy_Setting__c.Is_Exempt_From_Validation_X__c Steps: 1. Create `Hierarchy Custom Setting` 2. Add exemption field 3. Set `Org Wide Default` for this field to false 4. Set value to true for any `User` you wish to exempt from validation --- **Username** You can check against a `Username` in a way that at least works in all environments as follows: BEGINS($User.Username, "[email protected]") --- **User Id** I would not use this unless you have compelling reasons none of the above are a good fit: $User.Id = "00550000000lxVg"