Mixed DML Operation error occurs when Salesforce identifies an attempt within a single transaction to modify setup object data (such as Users or Permissions) and business object data (such as Accounts or Custom Objects) at the same time. Salesforce does not permit the execution of these two updates together.
When this happens, Salesforce stops the transaction and throws the Mixed DML Operation error to prevent inconsistent data changes.
You may see one of these messages:
Salesforce categorises objects into two groups,
These are configuration or access control records, such as:
(Users, Profiles, Permission Sets, Groups, Roles, Queues)
These are business data records, such as:
(Account, Contact, Opportunity, Case, Custom Objects)
Salesforce processes setup changes separately from business data to maintain security and data integrity. Updating both in the same transaction can cause conflicts, so the platform blocks it.
Move setup-related DML to run asynchronously using:
This splits operations into separate transactions, preventing the conflict.
Design your logic so that:
If the error shows up during deployment or testing:
This ensures setup and non-setup operations are isolated.
Check whether:
are updating setup or non-setup objects in the same execution. Breaking these into separate actions fixes the Mixed DML conflict.
Our Salesofrce experts can debug and resolve this issue quickly.