When changing the Virtual Machine Tier on theConfigure tab of a VM from Standard to Basic you may see the following error message:
Failed to configure virtual machine <VM name>
Expanding the error details will show:
The server encountered an internal error. Please retry the request. The long running operation tracking ID was: <operation ID>.
This is a known issue which we expect to fix in the next 1-2 weeks. In the meantime, the workaround to deploy a Basic VM is to delete and re-deploy the existing VM to a Basic VM size. For a virtual machine in a virtual network, you may need to re-deploy it to a new virtual network or to the same region (but not in a virtual network).
For a VM where the change to Basic was attempted and failed, when trying to recreate the VM you may be unable to reuse the existing disk. You will notice Attached To still shows the name of the deleted VM. If you encounter this issue with disk reuse, you will need to contact support to free up the disk. You will not be able to clear Attached To by trying to manually break the lease. Support options are listed at Microsoft Azure Support Options.
We will update this post once the overall issue has been resolved.
Thanks,
Craig