Problem Solved: Custom Image Hanging During Provisioning in Azure

Q. I uploaded my own image to Azure (an unsupported OS), but when I try to create a VM from the image it hangs at provisioning. Why?

A. An image in Azure is a VHD that has been prepared for duplication. For a Windows OS this means that SYSPREP has been run on the OS. When Azure deploys a VM based on a template as part of the provisioning process, an answer file is created and attached to the VM via a virtual DVD ISO file. The answer file format is based on the operating systems supported by Azure; it will not work on unsupported images such as client operating systems. This is why an unsupported OS gets stuck at the provisioning stage--it cannot process the answer file created by Azure.

If you need to use an unsupported OS in Azure, the solution is to not create it as an image that will use an answer file. Instead, create it as a regular disk that has not been SYSPREP'd, and therefore will not require the answer file specialization phase. The steps would therefore be:

This does mean the disk can be used by only one VM. If you need to use it for multiple VMs, you would need to duplicate it in Azure but still not use SYSPREP.