Hdd unmounting

I have an external hard drive connected to a pi via a powered usb hub. The problem is that everytime i remove it or i reboot the pi, it unmounts and i have to mount it again via ssh.
Is there a way to solve this problem?

How did you add the disk’s content to Volumio originally, or did you do it manually?

I had to mount the hdd manually the first time as well. With flash drives no problem