Command for mount SMB share give the error
mount.cifs //192.168.1.100/HDD /mnt/HDD -o credentials=/root/.smbcredentials,uid=osmc,gid=osmc
mount error(121): Remote I/O error
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)
/etc/fstab contained mount point (tried both versions 1.0 and 2.0) - OK.
root@Vero:/etc# cat /etc/fstab
#rootfs is not mounted in fstab as we do it via initramfs. Uncomment for remount (slower boot)
#/dev/vero-nand/root / ext4 defaults,noatime 0 0
//192.168.111.50/HDD /mnt/HDD cifs x-systemd.automount,noauto,iocharset=utf8,credentials=/home/osmc/.smbcredentials,uid=osmc,gid=osmc,file_mode=0770,dir_mode=0770,vers=1.0 0 0
Restarting mounting services - OK
root@Vero:/etc# mount -a
root@Vero:/etc# systemctl daemon-reload
root@Vero:/etc# systemctl restart remote-fs.target
Checking share availability - FAIL.
root@Vero:/etc# ls /mnt/HDD/
ls: cannot access '/mnt/HDD/': No such device
Well as starting points would first check availability of the share and the connection.
Install smbclient sudo apt-get install smbclient and then run smbclient -L 192.168.111.50 -U <your user> and show us the output.