Advance through the setup wizard. The VM will boot directly from the primary installation media, allowing you to click through the standard installation windows manually without looking for an external answer file. 3. Use an Alternative Boot Medium

If the issue persists, provide these details for deeper diagnosis

To solve a problem, one must first understand it. The error message, while appearing complex, points to a specific failure mode within Parallels Desktop. The term "unattended.iso" refers to a specially crafted ISO image file that contains, in its root directory, a configuration file, most commonly named autounattend.xml . This XML file is the heart of the unattended installation, providing all the answers to the setup questions Windows would normally ask a user.

: The installer expects the unattended answer file to be in a specific "location" (like a second virtual CD/DVD drive). If the VM cannot mount the ISO to that specific secondary drive, the connection fails. How to Fix It

If the setup still fails to progress after disconnecting the file, you can bypass the Parallels "Express Installation" feature entirely: 0;35f;0;358; Create a brand new virtual machine.

Instead of relying on the virtual drive connection that often fails, use these more stable methods: Method How it Works Why it’s "Better"