denon prime 4 crash help frozen screen and wont turn off
Hold powerbutton for a while. It will shut down. Or when there is no other possibilites, unplug device. Then you can normaly restart it with power on again.
Can you please also look for the crash-report ? - it should be saved on sd-card/ssd-drive or usb. This should be sent to denon via https://denondj.wetransfer.com/. This helps denon to look why the system crashed, and maybe other users then.