Open your hypervisor client (e.g., vSphere Client or VMware Workstation) and select .
Instead of using two separate ISOs, you can use a tool like AnyBurn or a PowerShell script to inject the autounattend.xml file directly into the root directory of your primary Windows 11 ISO. This removes the need for a second virtual drive entirely.
[Virtual Machine Settings] ├── CD/DVD (SATA 0:0) ──► points to Windows_11.iso └── CD/DVD 2 (SATA 0:1) ──► points to unattended.iso (Crucial for automation) Windows 11 cannot connect unattended.iso to CD/DVD
The most direct fix is ensuring the virtual machine actually possesses the hardware resource the automation script is looking for. the target Windows 11 virtual machine.
Move the containing your Windows ISO to the top of the list.
Here is how to bypass this and get your installation back on track. 1. The "Fast Start" Workaround (Hyper-V/VMware)
The official release notes for Parallels Desktop 18.3.1 list a direct fix for this very problem, noting that they fixed the bug where an error message saying Windows 11 cannot connect Unattended.iso to CD/DVD caused the unattended installation to fail.
You are not alone. This frustrating error has plagued system administrators, virtualization users, and power users since the release of Windows 11’s security-heavy 22H2 and 23H2 updates.