KQL – finding unmanaged disks

Unmanaged disks (aka classic Azure disks) where the VHD lives inside a storage account are end of life at the end of September 2025.

We have a handful that are underpinning some older appliances.

Finding them is a simple Kusto search:

resources

| where type == “microsoft.compute/virtualmachines”

| join kind=leftouter (ResourceContainers | where type==’microsoft.resources/subscriptions’ | project subscriptionName=name, subscriptionId) on subscriptionId

| where properties.storageProfile.osDisk.managedDisk == “”

| extend osDiskName = properties.storageProfile.osDisk.name

| extend osDiskUri = properties.storageProfile.osDisk.vhd.uri

| project subscriptionName,resourceGroup, vmName = name, osDiskName, osDiskUri

| union (

    resources

    | where type == “microsoft.compute/virtualmachines”

    | mvexpand dataDisk = properties.storageProfile.dataDisks

    | where dataDisk.managedDisk == “”

    | extend dataDiskName = dataDisk.name

    | extend dataDiskUri = dataDisk.vhd.uri

    | project  vmName = name, dataDiskName, dataDiskUri, resourceGroup

)