Clear List of shares

My tv is connected to a Raspberry Pi as part of my network via ethernet with OSMC installed. I have my tv records on USB-Harddisks attached to a MacMini and set as shares. I can see them on OSMC as Bonjour Volumes.
When I detach one of the HD’s from the MacMini, it is still listed as a data source in OSMC. I can choose it, but it shows the content of another shared HD.
How can I update the list of the shares?