main reason: having installed virtualbox before, there are multiple virtualboxes in the system. You can uninstall all virtualboxes first, and then install

again

. Uninstall all virtualbox:

sudo apt-get autoremove 'virtualbox*'

2. Reinstall:

sudo DPKG -i virtualbox – 5.2 _5. 2.6-120293 ~ Ubuntu ~ xenial_amd64. Deb