/sbin/mount.vboxsf: mounting failed with the error: Protocol error
19th April 2009
These days, my virtualisation needs are being well served by VirtualBox 2.2. Though it may be the closed source variant, I have no complaints about it. Along with a number of Windows VM's, I also have one running Ubuntu 9.04 and, for the first time, I seem to have VirtualBox's Guest Additions playing with a Linux guest as they should. Even the Shared Folders functionality is working.
However, I did get one problem when I tried out the last feature for the first time. The procedure is to issue a command like the following in a terminal session after creating the requisite directory in the file system and adding a host directory as a shared folder:
sudo mount -t vboxsf Music /mnt/host_music/
Above, Music is the name of the folder in the VirtualBox manager and /mnt/host_music in the directory in the guest file system. However, this returned the message at the head of this post at that first attempt:
/sbin/mount.vboxsf: mounting failed with the error: Protocol error
The solution thankfully turns out to be an easy one: reinstalling the Guest Additions, which certainly did the trick for me. The cause would appear to have been an update to Ubuntu, and 9.04 is understandably in a state of flux at the moment (I suspect kernel upgrades because of my previous experiences). Regardless of this, it is good to know that it's a problem with a simple fix, and I am seeing the niceties of a larger virtual screen system together with automatic grabbing and releasing of the mouse cursor too. While there may be a chance to explore the availability of these sorts of features to other Linux guests, I have other things that I should be doing and there's sunshine outside to be enjoyed.