Q. When creating an IaaS v2 VM under ARM can I use existing non-ARM storage accounts and virtual networks?

Q. When creating an IaaS v2 VM under ARM, can I use existing non-ARM storage accounts and virtual networks?

A. No. I

aaS v2 VMs that use Azure Resource Manager can only use storage accounts and virtual networks that were also created under ARM and are therefore also v2.

This means v2 and v1 Azure IaaS VMs cannot use the same virtual networks or storage accounts.