Good information... This is the whole VirtualBox article for archive purposes.
VirtualBox: Answers to frequent reader questions By Fred Langa on December 10, 2015
windowssecrets.com
Although Oracle’s free, open-source, virtual-PC application is a great way to safely test drive a new operating system or to keep an old OS alive, some of its complexities can be baffling.
Here are answers to some of the most common questions readers have sent in about setting up and using VirtualBox.
First, a quick refresher on virtual PCs
Simply put, virtual PCs (aka VPCs or virtual machines) are complete computing systems — hardware, OS, and apps — that are emulated entirely in software. For standalone applications (versus server setups), a VPC runs as a desktop application on a host system — typically a standard PC. VPC software often supports various versions of OSes; for example, VirtualBox lists support for Windows, Linux, Solaris, Apple’s OS X, and others.
Unlike a dual-boot system, a VPC lets you run two or more operating systems at the same time (shown in Figure 1) — and switch between them with just a click of the mouse. You can even set up shared folders and clipboards between the virtual and host systems.

Figure 1. Here, a fully functional Win7 (foreground) is running on an emulated PC — which in turn is running as an app on a physical Win10 machine.
VPCs isolate the OS and apps running inside them; by default, The VPC’s software runs just as if it were installed on a separate, real, physical PC.
By default, the VPC software isolates (sandboxes) the guest OS and its apps from the host system. In fact, the guest system is unaware that it’s running on an emulated PC. More important, whatever goes on inside the VPC is unlikely to have any effect on host-PC operations. For example, if the VPC-based OS crashes, the host system is typically fully protected and carries on without missing a beat.
VPCs have two major uses: One is to run an older OS and its apps inside a newer — often more secure — OS. This lets you continue to use software that might be obsolete or otherwise incompatible with current technology. For example, many Win7 users employ VPCs to continue running XP; or they use a virtual machine to run XP, Vista, and/or Win7 on a Win10 system (again, see Figure 1).
On the flip side, VPCs are ideal for testing operating systems and apps that might not be ready for prime time — or that need to be evaluated before you install them on your main system or systems.
Windows Secrets has featured several articles on using a VPC to safely test-drive and experiment with Android, Win8, and Win10, all without risking your primary machine. See, for example:
* “How to run Google’s Android OS on a Windows PC” – March 13, 2014, Top Story * “Step by step: How to safely test-drive Win8” – March 14, 2012, Top Story * “How to safely test-drive Win10 — step by step” – Oct. 16, 2014, Top Story Those articles are all based on Oracle’s VirtualBox ( site) VPC application. There are, of course, alternative VPCs, but VirtualBox is open-source and completely free. And unlike Microsoft’s free Hyper-V ( info), VirtualBox runs on all current versions of Windows — even older releases and Home editions.
VirtualBox’s documentation is excellent, but getting answers to apparently simple questions can be daunting. Although Oracle provides significant help, much of the information ( site) has been created by volunteers — many of whom are not technical writers.
That’s the overview. In the rest of this article, I’ll distill and answer several of the most common questions Windows Secrets readers have sent in about VirtualBox.
What are Guest Additions and Extension Packs?
Perhaps the two most puzzling aspects of VirtualBox are “Guest Additions” and “Extension Packs.” Many readers ask: “Do I need them?”
The confusion is understandable; a VirtualBox installation might comprise one, two, or three major components, in different combinations. These components include:
- VirtualBox platform package: This software contains the essential parts required for setting up and running bare-bones, generic, virtual machines on Windows, OS X, Linux, and other host operating systems.The open-source, platform-package files are available for free on the VirtualBox.org download page.
As of this writing, to run VirtualBox on a Windows host PC, you’d click the platform-package link VirtualBox 5.0.10 for Windows hosts – x86/amd64. (VirtualBox is regularly updated, so you might see a higher version number.)
- Guest Additions: These optional, open-source files provide numerous — and important — added functions that take VirtualBox VPCs beyond the basics. Guest Additions add features such as better video support (via custom, virtual video drivers), seamless mouse integration between the guest and host operating system, bidirectional clipboard support (to allow cutting and pasting between the host and guest OS), shared folders (a folder on the host PC can be accessed by one or more VPCs for easy file-sharing), and more.For a complete list of what’s available in the Windows Guest Addition packages, see section 4.2.1 of the online VirtualBox manual, “Guest Additions for Windows.”
The Guest Additions files aren’t downloaded separately; they’re bundled into the VirtualBox platform package download. However, Guest Additions are not automatically installed; they’re inserted into the guest system as a virtual CD (see Figure 2) and must be manually installed on each VPC.

Figure 2. The VirtualBox Guest Additions are inserted into each virtual machine via the VPC options menus
For step-by-step instructions on installing Guest Additions, see section 4.2.1 of the online manual, “Guest Additions for Windows.”
I highly recommend installing the Guest additions on all Windows VPCs. (Note: If you update to a newer version of VirtualBox, you should reinstall the Guest Additions.)
- Extension Packs: These files add advanced support for USB 2.0 and USB 3.0 devices, network booting, and several other functions. (For a full list, see section 1.5 of the VirtualBox online manual, “Installing VirtualBox and extension packs.”Extension Packs require a separate download from the VirtualBox.org download page. The current version is VirtualBox 5.0.10 Oracle VM VirtualBox Extension Pack. When the download is complete, double-click the file and it will automatically add the Extensions to the core Platform package.
Note: Extension Packs are not open-source files. However, Oracle provides them for free, under terms of theVirtualBox Personal Use and Evaluation License ( info), which covers private/personal/academic use and product evaluation. If you’re planning to deploy Extension Packs in a commercial or enterprise setting, see Oracle’s Licensing FAQ for more information.
Unless the licensing is a problem, I recommend installing Extension Packs. (If you update the core VirtualBox software, check whether there’s a new Extension Pack. VirtualBox works best if all components are current.) Issues with virtual hard-drive sizing
Here’s another common question is something like this: “What’s the right size for the virtual hard drives used by VPCs? I don’t want to give up too much space from my real OS and apps.”
VirtualBox, by default, creates virtual hard drives that use dynamic space allocation. It’s important to remember that the amount of disk space you specify when you first set up a virtual PC is the virtual drive’s maximum size. The actual space a virtual drive starts out using will typically be much smaller — only as large as it needs to be. It will then grow until it reaches the assigned maximum size.
In other words, regardless of a virtual drive’s size setting, it’ll consume only the amount of host drive space it currently needs.
For example, a clean, new, freshly created Win10 Pro-64 virtual machine with no additional software loaded, requires roughly 25GB of real disk space. Say you set the VPC’s virtual disk to 32GB (the amount VirtualBox suggests for Win10), the initial disk will still occupy only about 25GB of actual disk space on the host system. Then, as you use the new VPC — adding software, updates, and user files — the disk space will naturally grow until you reach the ceiling you initially set: 32GB, 50GB, 100GB, or whatever).

Figure 3. By default, a VirtualBox virtual disk uses only the space needed — and grows no larger than the ceiling you set.
The confusion about virtual-drive size leads many users to set the initial drive size too low, which then brings up this common question: “I’ve run out of space on my VPC’s virtual hard drive. How can I make it larger?”
There are three options:
- Use the VirtualBox Manager command line: This technique is a bit geeky, but it’s relatively quick, and it works.To start, shut down the VPC and open a command window on the host system. Navigate to the VirtualBox program folder (typically, Program Files\Oracle\VirtualBox) and enter the following command:
VBoxManage modifyhd [full path&name of target hard drive file] –resize [new size in MB]
Next, restart the VPC and use either Windows’ built-in disk manager or the third-party partition manager of your choice to expand the VPC’s primary disk partition to fill the newly created space.
For more information, see “How to resize a Virtual Drive” ( VirtualBox Forums), “How To Enlarge a Virtual Machine’s Disk in VirtualBox or VMware” (How-To Geek article), or “How to increase VirtualBox disk size in 9 easy steps” (Hajuria’s Blog).
- Transfer the Windows setup to a larger VPC: For this technique, you use disk imaging or a full-system backup. The process is less technically challenging, but takes much longer.Make a system image or backup of the too-small VPC and store the files in a safe location, off the VPC. Shut down the VPC and delete it from the VirtualBox management console. When asked, also delete all files associated with the old VPC.
Now create a new VPC with the disk size of your choice. Restore the disk image or backup to the new, empty VPC. Most restoration tools will let you restore the old image or back up to the new, larger disk. If the tool doesn’t, use a partition manager (Windows’ or a third party’s) to expand the restored image’s partition.
- Re-do everything from scratch: This is the simplest approach, but it’s also by far the most time-consuming. You simply wipe out the current VPC and create a new VPC with a larger drive. You then reinstall the OS and apps — and then restore your user files from backups.
Questions about licensing and Product Keys
No one wants to waste a Windows license, so many readers wonder: “Is a VPC a legitimate way to test Windows without buying new licenses? If I install Win10 on a virtual machine, will this prevent me from using the ‘free’ Win10 upgrade on my real PC later?”
A VPC test setup is completely legitimate, and it won’t affect a later, for-real, upgrade.
All current Windows versions allow for test installations. You simply skip the screen where you’re asked to provide a product key; you can also ignore the nags to activate. Windows will operate normally — though perhaps with some additional nag screens or limits on nonessential functions — for a month or more (the grace period varies by version and edition).
But in all cases, the core OS will be fully functional, and you’ll have enough time to get a feel for how the test version works — and to see whether it suits your needs.
When your test is done and you’re ready to move to the next version of Windows, just wipe out the VPC and upgrade the real, physical PC in the normal manner.
Other VirtualBox questions and concerns
Again, the VirtualBox online documentation ( site) can be unwieldy — and parts of it aren’t written with the utmost clarity — but it should answer most of your questions. Use the search option to zero in on the topic you’re researching. If needed, try different and varied keywords to conduct your search in different ways.
The VirtualBox online Community offers a wiki, chat, mailing list, and other functions that also can help answer your questions.
And finally, a general Web search with any of the major search engines can help answer almost anything. Use the termvirtualbox plus the specific item you’re asking about; for example, “virtualbox hard drive resize,” “virtualbox memory allocation,” “virtualbox shared folders,” and so on.
Once you get the hang of VirtualBox, I’ll bet you’ll find it an invaluable addition to your software toolbox!
Further reading on use and troubleshooting
VirtualBox is a complex platform for running and maintaining virtual machines. Here are some valuable resources from past LangaList Plus columns (paid content):
* “Solving problems with VirtualBox virtual PCs” ( Oct. 23, 2014) * “Virtual PC install kills host PC’s networking” ( May 14, 2015) * * * |