A system administrator encounters an error at run time that a record couldn't be updated...

When encountering an error at run time indicating that a record couldn't be updated during a Customizable Rollup operation, it is often due to validation rules on the target field that prevent the update.

Check the Target Field for Validation Rules:

Navigate to Setup > Object Manager.

Select the object that contains the target field.

Go to Fields & Relationships and find the target field.

Review any validation rules associated with this field to ensure they are not causing the update to fail.

Modify or Disable Validation Rules:

If a validation rule is causing the issue, consider modifying it to allow updates during the rollup operation.

Alternatively, temporarily disable the validation rule, perform the rollup operation, and then re-enable the validation rule.

Test the Rollup Operation:

After addressing any validation rules, rerun the Customizable Rollup operation to ensure that the error is resolved.

Monitor the operation to confirm that the updates are processed correctly without triggering validation errors.

By ensuring that validation rules on the target field do not interfere with the rollup operation, the consultant can resolve the error and ensure smooth data processing.