Mint 20 no shutdown

Linux Mint 20 ULYANA on USB 'live session user.
I get this on shutdown, in top left corner
[FAILED] failed unmounting /isodevice
[FAILED] failed unmounting /CdRom
Only way of shutdown is hold in on/off SW. this not being good at all.
OK
I now try terminal codes - sudo poweroff

sudo shutdown -h now
Both these end up with no shutdown just as above again.
Can anyone help please.
Thank you.
Ray