virtualbox.org

I found Ticket #17194 with the advice to install gcc solving the problem.
I run the actual Virtualbox on a Mac and have the same Problem. but I do not know how to install gcc. Please help me!

There is a FAQ that describes the minimum information needed for assistance.

As you are running VirtualBox on a Mac (your host) you don't need to install gcc there. The Guest Additions are installed and built in the guest OS (Ubuntu 17.10) and that is where you will need to install gcc and all its friends. You can do it with whichever of dpkg, apt-get, synaptic, etc. you are most comfortable with.

-Andy.

Thank You Andy.
Re minimum... i'm grown up allready, but yes i should ask in Ubuntu fores to get real help.

sudo apt-get install gcc: ... gcc is already newest version (4:7.2.0-1ubuntu1)
(I translated from German)

Can you please post the output of the installation attempt? Or a screen shot if you have to? Please do not post your whole desktop. Crop the image to the area of interest (for example, the Terminal of the guest). Also, if you're using a HiDPI setup, please shrink the image by at least 50%. Even better, change the DPI from 144 to 72, in Preview.app...

Guest addition 5.2.7 did it!

Great, thanks for the feedback. Marking as [Solved].
Could you also reply to ticket #17194 which you re-opened and state that it can be closed again?