VisualBox之所以在Linux上比傳統的VMware快得多，關鍵一點就是它和Linux內核的結合比較緊密，這也是開源的優點。
不過Linux內核更新很頻繁，每次更新內核后啟動VirtualBox都會提示：
VirtualBox kernel driver not installed. The vboxdrv kernel module was either not loaded or /dev/vboxdrv was not created for some reason. Re-setup the kernel module by executing ‘/etc/init.d/vboxdrv setup’ as root.
所以需要重新編譯VirtualBox的內核，Ubuntu下執行如下命令：
sudo /etc/init.d/vboxdrv setup
如果提示
* Stopping VirtualBox kernel modules [ OK ]
* Uninstalling old VirtualBox DKMS kernel modules [ OK ]
* Trying to register the VirtualBox kernel modules using DKMS
* Failed, trying without DKMS
* Recompiling VirtualBox kernel modules
* Look at /var/log/vbox-install.log to find out what went wrong
找到/var/log/vbox-install.log文件，內容大致為：
Makefile:172: *** Error: unable to find the sources of your current Linux kernel. Specify KERN_DIR=<directory> and run Make again. Stop.
所以需要安裝當前Linux內核的源文件，編譯VirtualBox內核的時候需要它，Ubuntu下執行如下命令安裝當前Linux內核的源文件：
sudo apt-get install linux-headers-`uname -r`
注意括起uname -r的不是單引號，而是Esc鍵下面的那個符號。
然后再編譯VirtualBox內核執行如下命令：
sudo /etc/init.d/vboxdrv setup