UnmodifiableEntity
IAM returns `UnmodifiableEntity` when a protected resource, typically a service-linked role, is managed only by the owning AWS service and cannot be changed directly. IAM returns HTTP 400 for this condition.
Last reviewed: February 8, 2026|Editorial standard: source-backed technical guidance
What Does Unmodifiable Entity Mean?
IAM blocked direct mutation because the target is service-managed (typically service-linked), so updates or deletion must be performed through the owning AWS service workflow.
Common Causes
- -Target IAM entity is service-linked and protected from direct modification.
- -Automation attempts to update/delete role fields managed only by owning AWS service.
- -Workflow treats service-linked role as standard customer-managed IAM entity.
- -Role lifecycle action was attempted outside the owning service control path.
How to Fix Unmodifiable Entity
- 1Identify owning AWS service for the service-linked role and use service-native workflow.
- 2Remove direct IAM mutate/delete actions for protected service-linked entities.
- 3Apply supported changes through the owning service configuration APIs.
- 4Retry only after switching to a supported service-managed lifecycle path.
Step-by-Step Diagnosis for Unmodifiable Entity
- 1Inspect role metadata to confirm service-linked role classification.
- 2Capture failing IAM operation and compare with service-linked role restrictions.
- 3Trace automation path that incorrectly treats the role as modifiable.
- 4Validate owning service runbook for approved role change operations.
Service-Linked Ownership Validation
- -Inspect role path/metadata to confirm service-linked ownership (example: role under
aws-service-role/is not customer-modifiable). - -Map blocked action to owning service lifecycle operation (example: role deletion must be initiated through service deprovision flow).
Automation Guardrails for Protected Entities
- -Audit IaC/cleanup jobs for direct IAM mutation attempts on service-linked roles (example: generic role cleanup job includes protected roles).
- -Enforce deny-list or classification checks before mutation APIs (example: skip update/delete when entity is marked service-managed).
How to Verify the Fix
- -Re-run workflow using service-managed path and confirm UnmodifiableEntity is cleared.
- -Validate target role remains consistent with owning service expectations.
- -Ensure no new direct-modification attempts hit protected entities.
How to Prevent Recurrence
- -Tag/classify service-linked roles and block direct IAM mutation paths in automation.
- -Add policy checks preventing delete/update actions on protected IAM entities.
- -Document service-owned role lifecycle handling across platform teams.
Pro Tip
- -query and cache
PathplusRoleLastUsedmetadata for service-linked roles, then route change requests to the owning AWS service API instead of IAM.
Decision Support
Compare Guide
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Official References
Provider Context
This guidance is specific to AWS services. Always validate implementation details against official provider documentation before deploying to production.