# Inactive and detached managed disk | Cloud Efficiency Hub Canonical: https://www.pointfive.co/efficiency-hub/inefficiencies/inactive-and-detached-managed-disk Managed Disks frequently remain detached after Azure virtual machines are deleted, reimaged, or reconfigured. By: Taylor Houck [Cloud Efficiency Hub](https://www.pointfive.co/efficiency-hub) # Inactive and Detached Managed Disk The short version Managed Disks frequently remain detached after Azure virtual machines are deleted, reimaged, or reconfigured. [Taylor Houck](https://www.linkedin.com/in/twhouck/) Cloud FinOps Specialist @ PointFive Azure service [Azure Managed Disks](https://www.pointfive.co/efficiency-hub/cloud-services/azure-managed-disks) Category [Storage](https://www.pointfive.co/efficiency-hub/service-category/storage) Reference CER-0039 Type Idle or Unused Resource ## Explanation Why the waste happens and who it affects. Some may be intentionally retained for reattachment, backup, or migration purposes, but many persist unintentionally due to the lack of automated cleanup processes. When these detached disks are also inactive-showing no read or write activity-they represent unnecessary ongoing costs. Identifying and removing these orphaned disks can produce meaningful savings without affecting any active workloads. ## Billing model The pricing dimensions that drive this cost. Managed Disks are billed based on: - Provisioned disk size (per GB/month) - billed regardless of attachment or usage - Disk types include: - Premium SSD (v1/v2) - High-performance workloads - Standard SSD - Balanced cost and performance - Standard HDD - Lower-cost for infrequent access - Ultra Disk - Provisioned with specific IOPS and throughput, billed separately - Snapshots - Billed separately based on storage consumed Unattached disks are fully billable until explicitly deleted ## How to detect 5 checks to find it in your estate. - Identify Managed Disks that are in an unattached state (not linked to any VM) - Review metrics or activity logs to determine whether the disk has seen any read or write operations during the lookback period - Check whether the disk is intentionally retained for recovery, migration, or reattachment - Determine whether a snapshot has already been created or is needed prior to deletion - Consult with workload owners or infrastructure teams to verify whether the disk still serves a business or technical purpose ## How to fix How to remove the waste. Delete inactive and detached Managed Disks that are no longer needed. If data retention is required, create a snapshot before deletion. Establish periodic reviews or automate cleanup of unused resources to reduce persistent storage costs, especially for higher-tier disk types. ## Documentation Vendor references for pricing and configuration. - [Azure Managed Disks Pricing azure.microsoft.com](https://azure.microsoft.com/en-us/pricing/details/managed-disks/) - [Azure Disk Storage Overview learn.microsoft.com](https://learn.microsoft.com/en-us/azure/virtual-machines/disks-types) ## Related inefficiencies [Browse the library](https://www.pointfive.co/efficiency-hub) - Azure Managed Disks CER-0074 ### [Managed Disk Attached to a Stopped VM](https://www.pointfive.co/efficiency-hub/inefficiencies/managed-disk-attached-to-a-stopped-vm) Disks attached to VMs that have been stopped for an extended period, particularly when showing no read or write activity, may indicate abandoned infrastructure or obsolete resources. Retaining these disks without validation leads to... Storage - Azure Managed Disks CER-0073 ### [Managed Disk Attached to a Deallocated VM](https://www.pointfive.co/efficiency-hub/inefficiencies/managed-disk-attached-to-a-deallocated-vm) A VM is deallocated but its attached managed disks are still active and incurring storage charges. While compute billing stops for deallocated VMs, the disks remain provisioned and billable. These disks often persist unintentionally after... Storage - Azure Managed Disks CER-0429 ### [Ultra Disk Compatibility Enabled Without an Attached Ultra Disk](https://www.pointfive.co/efficiency-hub/inefficiencies/ultra-disk-compatibility-enabled-without-an-attached-ultra-disk) To attach an Ultra Disk, a VM must first have Ultra Disk compatibility enabled, which allocates dedicated bandwidth between the VM and the block storage scale unit. Azure charges a reservation fee for this capability whenever it is enabled... Storage --- Source: the public page above. Product screenshots and illustrative interfaces are examples, not live customer data.