Q: I'm trying to run a 32-bit OS on Windows Azure IaaS but the virtual machine (VM) won't start--why?
A: Only 64-bit operating systems can run in Windows Azure IaaS--32-bit OSs will fail to start and aren't supported. Microsoft has a lit of supported OSs to be uploaded in a VHD.
Also remember that at time of writing, Azure IaaS doesn't support VHDX, so any VMs you upload must be in VHD format. You can convert VHDX to VHD using the Hyper-V Manager Edit Disk action or use this PowerShellcmdlet: