USB Volume shown after detaching from server

I had two external HD attached to my macmini. After detaching one of them, it is still listed in OSMC Files, even after rebooting. Strange: I can access it, and it shows the content of the other HD.
How can I update the list of files?

You don’t say how you are accessing the files.

If you have scanned both drives into the Library then unplugged one of the drives then yes, you would continue to see the listing of moves / tv shows that belong to the drive that was disconnected in the Library, but you would (of course) not be able to play them with the drive unplugged.

The library is not designed to automatically update to reflect whether various sources are connected or not. If the removal of the second drive is permanent, use the Library clean option in Settings to purge all the entries for files that are no longer there - this can take quite a few minutes.

Thanks for the advice.
I have my files on an external USB HD attached to my macmini and set as a share. I access the HD via zeroconf > smb.
I can see the detatched volume and it shows me the content of the HD that is still attached. I can - strange - play these videos without problems.
I am not shure I did the right action: In the main screen, I choosed Dateien (Files), then I clicked on the left Arrow on the kodi app and then I choosed ‘Bibliothek aktualisieren’ (eq. Library clean?). The text of the menu flows, but nothing seems to happen during the night. Today I updated OSMC as recommended, but the removed shares are still listed.
Is there a way to clean that list, or do I have to reinstall from scratch?