VirtualBox 4.3.20

VirtualBox is a powerful x86 and AMD64/Intel64 virtualization product for enterprise as well as home use. Targeted at server, desktop and embedded use, it is now the only professional-quality virtualization solution that is also Open Source Software.

Some of the features of VirtualBox are:

Modularity. VirtualBox has an extremely modular design with well-defined internal programming interfaces and a client/server design. This makes it easy to control it from several interfaces at once: for example, you can start a virtual machine in a typical virtual machine GUI and then control that machine from the command line, or possibly remotely. VirtualBox also comes with a full Software Development Kit: even though it is Open Source Software, you don't have to hack the source to write a new interface for VirtualBox.
Virtual machine descriptions in XML. The configuration settings of virtual machines are stored entirely in XML and are independent of the local machines. Virtual machine definitions can therefore easily be ported to other computers.

VirtualBox 4.3.20 is a maintenance release. The following items were fixed and/or added:

VMM: fixed reboot hang of 32-bit Windows SMP guests (bug #13319, #13462)
VMM: proper Math Fault handling with certain legacy guests (bug #9042, AMD hosts)
VMM: fixed a Guru Meditation VINF_EM_TRIPLE_FAULT on older CPUs that don't support MSR-bitmaps (VT-x only; bugs #13034, #13125, #13311, #13425, #13426, #13463, #13585)
GUI: fix 3D overlay window re-parenting issue when VM goes to full screen mode on X11 hosts.
GUI: fix occasional loss of focus in full-screen mode on X11 host systems (4.3.16 regression)
GUI: Mac OS X: wizards should have Cancel button (bug #12541)
GUI: added a global option to prevent automatic raising of the new window by mouse move with multi-screen guests (bug #8878)
API: accept remote display port 0 as the default RDP port (bug #8534)
VBoxManage: fixed crash when executing showvminfo command under certain circumstances (bug #13190)
ACPI: fixed occasional Guru Meditations in ACPI timer code (4.3.18 regression; bug #13521)
EFI: improved performance of IDE disk access
EFI: fixed a bug in the EFI video driver which prevented Windows to boot in UEFI mode (bug #12022)
EFI: properly announce the amount of RAM for big VMs (bugs #11103 and #13211)
Storage: fixed a crash under certain circumstances when a medium was ejected from a drive attached to the SATA controller without inserting a new medium before pausing or closing the VM (4.3.16 regression)
Storage: fixed an interrupt acknowledge issue causing hanging guests or slower I/O (4.3.18 regression)
Storage: fixed broken resume after the VM was suspended due to a full disk if host I/O caching is used
Storage: fixed a Guru Meditation under certain conditions when using the DevLsiLogic controller with VMs running in raw mode (4.3 regression; bugs #12254, #12655, #12709, #12774, #12886)
Guest Control: fixed a bug which might lead to a crash during recursive copy
SDK: Java COM bindings fixes
iPXE: enable the HTTP download protocol (bug #13628)
Runtime: do not use a fixed stack size creating temporary threads during initialization (bug #13038)
Windows hosts: fixed more startup problems on certain Windows hosts due to conflicts with anti-virus software; better error reporting (4.3.14 regression; bug #13187)
Windows hosts: fixed DirectSound host audio failure under certain conditions (bug #13418)
Windows hosts: fixed additional cases of 4.3.14 regression whereby AltGr stopped working for some people (bug #13216)
Windows Additions: preserve guest monitor layout when resizing Windows 7 or newer guests
Linux Additions: Linux 3.18 compile fixes (bug #13515)