virtualbox.org

Hello IamSteve:
I'm new to OpenSuse. This is the first time I've tried it as a linux guest. Probably only one month has passed since I first installed it.
Yesterday, I allowed it to install updates but afterwards the shared folder was no longer shared! The symptoms were similar to yours ... the folder itself was there but the contents of the folder was empty.
My setup was a bit different from yours in that I had the 5.0.20 guest additions installed. Re-installing the guest additions caused the shared folders to return as before!

As a first attempt, you could go to the Yast Software Management, delete the three virtualbox-guest-* entries, and reinstall them; your shared folders may start working again ... maybe! If you want to install the 5.0.20 guest additions as I did, you can try the steps below.

First, uninstall the three virtualbox-guest-* entries that come preloaded. Then (as suggest in another forum post "Guest Additions on OpenSUSE 42.1 Not Working Correctly" (sorry, as this is my first post I couldn't post the link)), mark them as "Taboo - Never Install" so that they are not re-installed during an OpenSuse update.
The next steps are from the Virtualbox User Manual (version 5.0.20):
> sudo zypper update
> sudo zypper install make gcc
> Shutdown/Restart
> sudo zypper install kernel-default-devel
> sudo apt-get install dkms
> From the virtual machine menu: Devices > Insert guest addition CD image
> cd /run/media/<username>/VBOXADDITIONS_5.0.20_106931
> sudo sh ./VBoxLinuxAdditions.run (This uninstalls and re-installs the guest additions)
> You may have to re-add the user to the vboxsf group:
sudo usermod -a -G vboxsf <username>
> Shutdown/Restart
Hopefully that works! Do a snapshot before you being so you can backout if things don't go well.
Regards

To Perry and the kind people who thought along with me: here's another update.

I didn't do much about the problem because I just didn't have the time - a test to write and stuff. But now apparently the incredible thing happened: The next update for the Leap guest additions slightly changed the pattern of errors, but did nothing essential. But when I now updated to 5.0.24, apparently someone has noticed the problem and done something about it, because according to first experiments the shared folder works again. I did nothing of consequence, must've been the update. The change log does not say anything about it that I can discern, but evidently something has been repaired. Hope it holds...

All the best to everyone,

Steve :- )