How do you force a CIFS connection to unmount

Question

I have a CIFS share mounted on a Linux machine. The CIFS server is down, or the internet connection is down, and anything that touches the CIFS mount now takes several minutes

Answer 1

umount -f -t cifs -l /mnt &

Be careful of &, let umount run in background. umount will detach filesystem first, so you will find nothing abount /mnt. If you run df command, then it will umount /mnt forcibly.