CostLensUnattached Managed Disk (Azure)
Unattached Managed Disk (Azure)
CostLens finds Azure managed disks in the Unattached state — billing full storage rates while connected to nothing.
Updated July 20261 min read
CostLens finds unattached Azure managed disks — disks in the Unattached state, connected to no VM yet billing full provisioned-capacity rates. These are a common leftover after deleting a VM without deleting its data disks.
Deletion is irreversible
Deleting a managed disk permanently destroys its data. CostLens shows this as an irreversible fix and cannot roll it back. Snapshot the disk first if you might need the data.
How it works
Disks are enumerated
CostLens lists managed disks via the Azure Resource Manager API and checks each disk's diskState.
Unattached disks are flagged
Disks in the Unattached state are surfaced, priced at their provisioned size and SKU (Premium/Standard SSD/HDD).
What to do
- Confirm the disk is truly orphaned and not a spare kept intentionally.
- If you may need the data, create a snapshot first.
- Delete the disk to stop the charge — via CostLens Apply Fix (irreversible) once write access is granted, or in the Azure portal.
Severity levels
| Severity | Estimated monthly savings |
|---|---|
| critical | >$500 |
| high | $100–$500 |
| medium | $20–$100 |
| low | <$20 |
Required permissions
- Detect:
Reader— see Azure Accounts. - Apply Fix (delete): a write role with
Microsoft.Compute/disks/delete.
Limitations
- Deleting a disk that backs a stopped/deallocated VM will break that VM — CostLens only flags disks reported as
Unattached.