Oracle VM VirtualBox is an industrial-strength open source virtualisation tool that makes it easy to create virtual machines (VMs), simulated computers that run on your PC but act as though they were separate systems. It's a powerful capability that has many different applications.

If you'd like a closer look at Windows 10 before you upgrade, for instance, then you could install Microsoft's latest in a VM, then access it in a window on your XP or Vista desktop.

Or maybe you've upgraded to Windows 10 and find a favourite old app doesn't work any more? Create a Windows XP VM and you might be able to run it again.

VirtualBox can also be a useful security tool: if you download and test apps in a VM, then any malware you might encounter will be isolated from your main system.

And it's the perfect choice if you want to try out another operating system with the minimum of hassle. Right now you can install Google Chrome OS, all the mainstream Linux variants (2.4 and 2.6), OpenBSD, OS/2, ReactOS, SkyOS, DOS, and just about every version of Windows there's ever been. (Of course you'll need to have the system discs to hand.)

VirtualBox 6 included an interface redesign, making it easier to view and manage your virtual machines. VM displays can now be scaled, so you can reduce a window size by half (for instance) and still see everything that's going on. The ability to limit a VM's CPU and IO time means the program will be less of a drain on your system's resources, and there are a host of other performance optimisations and bug fixes available.

What's new in VirtualBox 6.1.4 (see changelog for more)?

- Virtualization core: Fixed a rare issue with ICEBP instruction causing guru meditations on Intel hosts (6.1.0 regression; bug #19171)
- Virtualization core: Fixed macOS Catalina guests failing to boot after upgrading to 10.15.2 onwards (bug #19188)
- GUI: recent NLS integration and bug fixes for GUI and Qt translation tags
- USB: Fix isochronous transfers to the VM for xHCI
- Serial: Fix buffer handling, avoiding receiving stale data when the receive queue is flushed (bug #18671)
- Serial: Improve host serial port passthrough handling on Windows host
- VBoxManage: Restore old --clipboard option for modifyvm command
- macOS host: Use hardened runtime and request the needed entitlements, meeting latest notarization rules which also required moving VirtualBoxVM executable
- macOS host: Update osxfuse to v3.10.4
- Windows host: Update Italian translation of installer
- Windows host: Improve shared folder compatibility with POSIX append semantic (bug #19003)
- Windows host: Restore the ability to run VMs through Hyper-V, at the expense of performance
- Linux guest: Support Linux 5.5 (bug #19145)
- Linux guest: Shared folder fix for loopback mounting of images
- BIOS: Always report non-ATA disks as ready
- BIOS: Report EFI support through DMI table (bug 19144)
- VGA BIOS: Reduce stack space usage for INT 10h handlers

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This professional quality virtualization package must be one of the most powerful open source tools around