Just an update for people that might be looking at this thread The issue is with Proxmox Display settings. Instead of using default, try changing to VirtIO-GPU (virtio) or other display adapters and see if it will fix it. I'm personally using VirtIO-GPU and got it working The garbled output actually doesn't matter, it will still boot up in the background. I got a working instance of unRAID after waiting a while even with the garbled output on Proxmox.