Can't Start VM with Custom NAT Network on macOS (VERR_INVALID_STATE)

[BARERM]

I'm trying to use a custom NAT network instead of the default "NAT" mode for my Ubuntu VM in VirtualBox on macOS. Here's what happens:

I created a NAT network named "NatNetwork" in VirtualBox with default settings (10.0.2.0/24, DHCP enabled).
I changed my VM's network adapter to use this NAT network.
When starting the VM, I get this error:
Failed to open/create the internal network 'NatNetwork' (VERR_INVALID_STATE).
Failed to attach the network LUN (VERR_INVALID_STATE).
NS_ERROR_FAILURE (0x80004005)

Additional info:

Host: macOS Sequoia 15.6 (M3 chip)
VirtualBox version: [your version here]
Guest: Ubuntu 24.04.3 LTS
Things I've tried:

Checking if the NAT network exists (it does)
Verifying no virtual network interfaces (vboxnet*) show up in ifconfig
Recreating the NAT network through command line
The VM works fine with default NAT mode, but fails when using the custom NAT network. Any suggestions for fixing this?

[leglagla]

Hello !

I have the same problem. I’m experiencing a persistent issue with VirtualBox on macOS Sequoia 15.6 (M4 Pro chip)

I’m unable to use a custom NAT Network for my virtual machines (Ubuntu Server, Windows 11 ARM, Windows Server 25 arm).
Default NAT and Bridged modes work flawlessly.
As soon as I switch to a custom NAT Network ("NatNetwork" with subnet 10.0.2.0/24), I get the same error when starting the VM.

Have you found a workaround or solution (a specific VirtualBox version or hidden setting) ?
Could this be related to compatibility issues with Apple Silicon or a known bug in Sequoia?

I’d really appreciate any insights or suggestions! I’ll update this post if I find a fix.

[UPDATE : I updated VB 7.2.0 to 7.2.2 and it's solved, thanks for the update !]