VirtualBox, an open source x86 virtualization project available for free has just hit version 4.1.20. The new version, a 101.3 megabyte download, features the following fixes and changes:

- VMM: fixed a crash under rare circumstances for VMs running without hardware virtualization.

- VMM: fixed a code analysis bug for certain displacement instructions for VMs running without hardware virtualization.

- VMM: fixed an interpretion bug for TPR read instructions under rare conditions (AMD-V only).

- Snapshots: fixed a crash when restoring an old snapshot when powering off a VM (bugs #9604, #10491).

- VBoxSVC: be more tolerant against environment variables with strange encodings (bug #8780).

- VGA: fixed wrong access check which might cause a crash under certain conditions.

- NAT: final fix for crashes under rare conditions (bug #10513).

- Virtio-net: fixed the problem with receiving of GSO packets in Windows XP guests causing packet loss in host-to-VM transfers.

- HPET: several fixes (bugs #10170, #10306).

- Clipboard: disable the clipboard by default for new VMs.

- BIOS: the PCI BIOS was not properly detected with the chipset type set to ICH9 (bugs #9301, #10327).

- Mac OS X hosts: adaptions to OS X 10.8 Mountain Lion.

- Linux Installer: fixes for Gentoo Linux (bug #10642).

- Linux guests: fixed mouse integration on Fedora 17 guests (bug #2306).

- Linux Additions: compile fixes for RHEL/CentOS 6.3 (bug #10756).

- Linux Additions: compile fixes for Linux 3.5-rc1 and Linux 3.6-rc1 (bug #10709).

- Solaris host: fixed a guru meditation while allocating large pages (bug #10600).

- Solaris host: fixed possible kernel panics while freeing memory.

- Solaris Installer: fixed missing icon for menu and desktop shortcuts.

VirtualBox 4.1.20 is available for free and requires an Intel-based Mac running Mac OS X 10.5 or later and an Intel-based Mac to install and run.

If you’ve tried the new version and have any feedback, please let us know.