Hello marceus,
Thanks for your query.
Please follow this document to find and delete unattached Azure managed and unmanaged disks:
Find and delete unattached Azure managed and unmanaged disks
When you delete a virtual machine (VM) in Azure, by default, any disks that are attached to the VM aren't deleted. This feature helps to prevent data loss due to the unintentional deletion of VMs. After a VM is deleted, you will continue to pay for unattached disks. This article shows you how to find and delete any unattached disks and reduce unnecessary costs.
This is a similar discussion thread in Q&A forum, please refer to the suggestion and let me know the status.
This issue typically occurs when you are requesting an operation that is not permitted in the resource's current state.
You may try deleting the Resource Group from the https://resources.azure.com/, and see if helps. Refer Azure Resource Explorer for more details.
If the issue still persists, we would like to work closer on this issue, could you please reach to us via AZCommunity[AT]microsoft.com with a link to this Issue as well as your subscription ID and the resource group name, please mention "ATTN anand" in the subject field.
Hope this helps!
Kindly let us know if the above helps or you need further assistance on this issue.
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