virtualbox.org

Using VirtualBox 5.0.16, I created and installed an Ubuntu 14.04 virtual machine containing Linux kernel 3.19.0-25-generic, installed the Guest Additions, and proceeded to work quite happily with a couple of shared folders from my Win7 host. I then installed Linux kernel 4.1.18, and could no longer see my shared folders, except for the top "sf_..." directories. I re-installed the Guest Additions, hoping this would solve the problem. No joy. Now, when I switch back to the 3.19.0 kernel, I can see and work with my shared folders, but when I switch back to the 4.1.18 kernel, they disappear. I suspect that, since 4.1.18 is relatively new, Oracle has yet to support it. Has anyone else encountered this problem, and, if so, successfully found a way around it? Any help would be greatly appreciated.

We are using up to kernel 4.5 so it should not be the real issue. Usually it is due to the guest additions not being upgraded, or properly built against the new running kernel. Boot to the new kernel and then remove the guest additions and install them again. If this fails then post the guests log file ( as an attachment )

Note: this depends on you running the official builds of VirtualBox and guest additions.

So, I re-ran the Guest additions once again automatically with 4.1.18. The messages that came out indicated that the Guest Additions were removed and rebuilt (I couldn't find any other way to remove the Guest Additions other than re-running the "CD.") If you can tell me where I can find the guests log file, I will attach it. Thanks.

Post the guests log file ( as an attachment ). Right click on the guest in the Main Manager then click show log. Save and post as an attachment. Compress if it is too large to post.

Her is the guests log. I've been switching back-and-forth between my 4.1.18 and my 3.19.0, so there were a bunch of reboots. But, I did confirm that Guest Addition build are kernel-specific, and the 4.1.18-built additions didn't work when I went back to 3.19.0, but the rebuild on 3.19 again brought the shared folders right back. Thank you for your help. I'll be off-line, probably for the entire weekend.

Assuming that you had switched to the new kernel and this log is from that, I see the mount was successful as far as VirtualBox is concerned.

• 1) can you confirm that /media/sf_* does not exist?
  2) also post the following as an attachment: /var/log/vboxadd-install.log