: On macOS (common with Parallels), the application may lack permission to create or access the temporary ISO in the system's temporary folders. Top Solutions 1. Shift to a Manual Installation

: windows 11 cannot connect unattended.iso to cd dvd 2, VirtualBox unattended ISO error, CD/DVD 2 mounting failure, Windows 11 VM secondary optical drive, fix unattended installation.

Last updated: 2025-10-03. For further assistance, visit the VirtualBox forums or Microsoft Q&A with your VM log files attached.

Windows 11 enforces Secure Boot and driver signature verification. A custom unattended ISO without valid boot signatures may be rejected by the guest Windows 11 OS, causing the hypervisor to report a "cannot connect" error because the guest OS never acknowledges the drive.

Remove any secondary CD/DVD drives or set them to or "Disconnect" before restarting the installation. 3. Create a Custom ISO with Rufus

: It forces the hypervisor to release the secondary drive before Windows asks for it again.

: Disable EFI in the hardware page of the new VM wizard if the unattended installation keeps "croaking" at the boot stage. Windows 11 cannot connect unattended.iso to CD/DVD

Instead of relying on the hypervisor to manage two separate disks (one for Windows and one for the unattended file), you can combine them into one. Use an ISO editor to open your official Windows 11 image.