# Unused AMIs Retaining Snapshot Storage | Cloud Efficiency Hub Canonical: https://www.pointfive.co/efficiency-hub/inefficiencies/unused-amis-retaining-snapshot-storage Image pipelines, patching workflows, backup scripts and deployment tools create Amazon Machine Images continuously, and old AMIs are rarely deregistered. By: PointFive Updated: 2026-09-28 [Cloud Efficiency Hub](https://www.pointfive.co/efficiency-hub) The short version Image pipelines, patching workflows, backup scripts and deployment tools create Amazon Machine Images continuously, and old AMIs are rarely deregistered. PointFive Research Cloud cost research at PointFive AWS service [AWS EC2](https://www.pointfive.co/efficiency-hub/cloud-services/aws-ec2) Category [Storage](https://www.pointfive.co/efficiency-hub/service-category/storage) Reference CER-0345 Type Idle or Unused Resource ## Explanation Why the waste happens and who it affects. An EBS-backed AMI has no charge of its own, but it keeps its backing EBS snapshots, which are billed for storage every month and cannot be deleted while a registered AMI still uses them. Accounts with nightly or per-commit image builds can accumulate thousands of AMIs whose snapshots nobody will ever launch from again. Cleanup is often incomplete even when AMIs are deregistered: by default, deregistering an AMI does not delete its snapshots, which continue to incur storage costs. The EC2 User Guide calls this out under avoiding costs from unused resources and recommends deleting associated snapshots during or after deregistration. Because the snapshots were created by CreateImage rather than by a backup policy, they also tend to fall outside snapshot retention rules. ## Billing model The pricing dimensions that drive this cost. AMI registration EBS-backed AMIs have no separate charge; the cost is the storage of their backing snapshots Snapshot storage Billed per GB-month for the data stored in each snapshot, for as long as the snapshot exists Deregistration default Deregistering an AMI leaves its snapshots in place and billing unless they are deleted explicitly S3-backed AMIs Older instance store-backed AMIs keep their bundle files in Amazon S3, billed as S3 storage until deleted ## How to detect 5 checks to find it in your estate. - List AMIs you own with describe-images --owners self and flag those whose LastLaunchedTime is older than your threshold or absent (usage is reported with a 24-hour delay and tracked since April 2017) - Before flagging, check whether any launch template, Auto Scaling group, Image Builder recipe or other account (through launch permissions) still references the AMI - Find orphaned snapshots left behind by past deregistrations: snapshots whose description has the form Created by CreateImage(i-...) for ami-... where that AMI ID no longer exists - Review disabled and deprecated AMIs that are still registered, since they keep their snapshots and storage charges - Sum the snapshot storage attached to each AMI (via the snapshot IDs in its block device mappings) to prioritize the largest images ## How to fix 5 ways to remove the waste. - Deregister AMIs that are no longer needed with deregister-image --delete-associated-snapshots (or the Delete associated snapshots option in the console); snapshots shared with other AMIs are not deleted, and AMIs managed by AWS Backup must be removed by deleting their recovery points in AWS Backup instead - Delete orphaned CreateImage snapshots that no remaining AMI references - For AMIs produced by EC2 Image Builder pipelines, add Image Builder lifecycle policies to deprecate, disable and delete old image versions and their snapshots automatically - For AMIs created by Data Lifecycle Manager AMI policies, set count- or age-based retention; DLM deletes backing snapshots automatically when it deregisters an AMI - If a Recycle Bin retention rule covers AMIs or snapshots, account for the retention period, since resources in the Recycle Bin are still billed until they are permanently deleted ## Documentation Vendor references for pricing and configuration. - [Deregister an Amazon EC2 AMI docs.aws.amazon.com](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/deregister-ami.html) - [Check when an Amazon EC2 AMI was last used docs.aws.amazon.com](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ami-last-launched-time.html) - [Manage lifecycle policies for Image Builder images docs.aws.amazon.com](https://docs.aws.amazon.com/imagebuilder/latest/userguide/manage-image-lifecycles.html) - [Create Amazon Data Lifecycle Manager custom policy for EBS-backed AMIs docs.aws.amazon.com](https://docs.aws.amazon.com/ebs/latest/userguide/ami-policy.html) - [Amazon EBS pricing aws.amazon.com](https://aws.amazon.com/ebs/pricing/) ## Related inefficiencies [Browse the library](https://www.pointfive.co/efficiency-hub) - AWS EC2 CER-0083 ### [Stale Dedicated Hosts for Stopped EC2 Mac Instances](https://www.pointfive.co/efficiency-hub/inefficiencies/stale-dedicated-hosts-for-stopped-ec2-mac-instances) When an EC2 Mac instance is stopped or terminated, its associated dedicated host remains allocated by default. Because Mac instances run only on Dedicated Hosts (one instance per host) and the host, not the instance, is the unit of... Compute - AWS EC2 CER-0034 ### [Inactive EC2 Instance](https://www.pointfive.co/efficiency-hub/inefficiencies/inactive-ec2-instance) An EC2 instance remains in a running state but is not actively utilized. These instances may be remnants of past projects, forgotten development environments, or temporarily created for testing and never decommissioned. If an instance... Compute - AWS EC2 CER-0342 ### [Unused EC2 On-Demand Capacity Reservations](https://www.pointfive.co/efficiency-hub/inefficiencies/unused-ec2-on-demand-capacity-reservations) On-Demand Capacity Reservations (ODCRs) hold EC2 capacity for a specific instance type, platform, tenancy and Availability Zone. They are billed at the equivalent On-Demand rate for every reserved slot whether or not an instance is running... Compute --- Source: the public page above. 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