Memento wrote: ↑8. Sep 2023, 18:55
If I would install "Virtualbox-guest-utils" package alone, then shared folder would work, but shared clipboard would not. On the other hand, if I install only built-in Guest Additions, then shared clipboard would work, but not shared folder. Also, installing them in reverse order didn't work.
As an explanation for the casual reader: The VirtualBox Guest Additions as provided by Debian/Ubuntu/Mint come in several separate packages, whereas Oracle provides them in a single package. For each installed VirtualBox software component, the last one installed wins, and therefore you've got a mixture.