If you’re on a Windows host PC and you installed Ubuntu on a virtual machine e.g. a VHD and when you try to mount a share to access some common files, then you might get the error “Unknown filesystem”.

Important: Share a folder on the host OS with the guest OS (virtualbox) and not the other way around. It is possible you are attempting to share a folder incorrectly

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While you’re on Ubuntu make sure to run the guest additions ISO using this command

sudo apt-get install linux-headers-generic

Are you trying to install this on CentOS? Issue the following command:

yum install kernel-headers kernel-devel --disableexcludes=all

If you don’t, you will end up getting the error “No package available” for the kernel-headers package.

Building Virtualbox Guest Additions.png

The 1st Error: Unknown Filesystem

1. Step If you get this or a similar error: Unknown Filesystem Type Vboxsf” when trying to mount a share so you can access it on Windows 7 or 8, then proceed below
Unknown Filesystem Type Vboxsf.png

The 1st Solution

2. Step Enter this one a new line: apt-get install virtualbox-ose-guest-utils – keep in mind this works on Ubuntu and Debian but if you’re on CentOS, you may need to use yum to install aptitude first!

Virtualbox Guest Utilities.png

The 2nd Error: Unable to locate package virtualbox-ose-guest-utils

1. Step Enter apt-get install virtualbox-guest-additions
Unable To Locate Virtualbox Ose Guest Utils.png

2. Step You might the error “Package virtualbox-guest-additions is not available”. If so, enter apt-get install virtualbox-guest-additions-iso

Apt Get Install Guest Additions Iso.png

3. Step You now have to download about 65MB of files, so have some patience – confirm with Y

Error: Building the main Guest Additions module FAILED

If you keep getting this error, make sure to run this command:

yum install kernel-headers kernel-devel --disableexcludes=all