How to detect unattached managed disks.
Unattached Managed Disks can quietly add recurring Azure cost when resource state, utilization, or lifecycle policy no longer matches real usage. This guide explains why it costs money, how to find it manually, and how Costframe detects it read-only.
Unattached Managed Disks
Orphaned unattached managed disks found in billing records with zero active workload associations over a rolling 30-day window.
Operational Description
When a virtual machine is destroyed or deprovisioned, its associated managed OS and data disks are frequently left behind in the subscription. Because Azure continues to preserve the data blocks, these unattached disks are billed at standard storage rates indefinitely.
Primary Root Cause
Infrastructure-as-code scripts or manual tear-downs that remove the Virtual Machine compute resource but fail to specify deletion policies for attached managed disks.
How Costframe Detects & Verifies This
We scan the Azure Resource Graph for resources of type Microsoft.Compute/disks where the diskState attribute is exactly equal to 'Unattached' and cross-reference them with active disk IOPS telemetry.
Continuous cloud audits, automated
Run this detector and dozens of other cloud-waste rules across all your Azure subscriptions continuously.