I recently found a neat way to dual boot Windows operating systems on a PC without partitioning the hard drive, adding entries to the boot menu, and risking slower computer boot-up (or boot errors in extreme cases. Believe me, I’ve been down that road). The process consists of installing Windows to a USB flash drive or HDD and booting the computer directly from it. So essentially, you can carry around a “computer” the size of a flash drive, and you can bring your files, programs, drivers, and settings with you wherever (such as using the device on your work and home PC) . The first (unofficial) “portable Windows” was originally done with Windows 7 using command-line deployment  tools (mainly WAIK, but DISM was used later as well). Then Microsoft announced a new feature built into Windows 8 Enterprise called “Windows To Go”, which was the first official USB-bootable and completely portable version of Windows, and was a big step up from Windows 7 for dual booting due to built-in USB 3.0 support.

Sorry, I had to include the history lesson. So fast-forward to now, and dual booting with USB is now much more available to the public and easy to do yourself (without Windows 8 Enterprise). A tool from www.easyuefi.com called WinToUSB does the job for you and has a nice GUI as well. The 2 most awesome things about this program are:

  1. It’s free (I like free software).
  2. It supports Windows 7, 8, 8.1, and 10 (all versions, from Home to Pro, 32 & 64 bit).

As a side note, please don’t think I am insulting your intelligence with these directions as I have no idea of your level of computer expertise. I believe dual booting is probably only cool for boring people like me.

One thing that I really recommend for your flash drive is that it be USB 3.0 or better, since 2.0 is WAY too slow and the awesomeness of USB dual booting would likely be lost on you. If your computer only has USB 2.0 ports, then only go ahead if you are naturally a patient person (I am not). Also keep in mind that Windows 7 doesn’t have built-in USB 3.0 support. I would recommend using only Windows 8 and 10 for Windows-To-Go. The program has 3 major steps, and all the directions are also on the Easy UEFI website.

You will need 3 things:

  1. A flash drive or USB HDD with at least 16 GB (like I said, preferably 3.0) Make sure you don’t care about anything on the device or that it is empty, since the installation formats the device.
  2. An ISO of the operating system you want to dual-boot (Windows 7,8,8.1, or 10). Keep reading for how to get the ISO if you don’t have one.
  3. A PC that can boot from a USB device and preferably has USB 3.0 support. Macintosh people, you’re on your own. Mac has been completely outside my expertise for a decade and half, and will stay that way for the foreseeable future.

You can obtain an ISO of all supported Windows OS with this tool: ISO downloader. If the link didn’t work, go to http://www.heidoc.net and look for their Windows ISO download tool. Don’t worry if you don’t have a product key, I have run Windows with no product key and the worst things you have to deal with are an occasional activation prompt and a small logo watermark on the desktop. Remember, this is just a fun experiment for most people, and we are not going to make money or anything off this. Consider it VirtualBox, only with the full CPU threads.

The directions on the Easy UEFI website are not 100% clear on this: make sure you know whether or not your USB device is classified by your PC as “removable” or “fixed”. This can really wreck your experience if you don’t have this straight from the get-go. An easy way to find out is this: plug in your device and find it under “My PC” or “My Computer.” When you find its icon in the list, right click it and click “Properties” on the pop-up menu. Under general information, your device will either be labeled as “Basic (fixed) Disk” or “Removable Device (disk)”.

If your device is “removable”, the process is very simple. Run the WinToUSB tool and find the ISO on your computer, select the device and let it format it for you, then opt to install the boot and system files to the same single partition. The installation on a removable drive is VHD-based with WinToUsb, since Windows 8 cannot be booted the standard (legacy) way from a removable flash drive. There is no way around this, but it is fine for most applications. Removable drives have to be booted with legacy BIOS, since Windows will not recognize the other NTFS OS partition besides the FAT32 system partition. If you don’t know what I am talking about, keep reading. If your PC is BIOS based, you won’t know the difference. If UEFI based, you will have to tweak BIOS settings. Skip past the next paragraph to get directions on how to do this.

If your device is “fixed” or “basic”, then things are more complicated. If you want to boot the device on both UEFI and BIOS based computers (which only makes sense for a portable system) you will need to go to Disk Management (under Control Panel) and convert the disk partition scheme to MBR first, then create a primary system partition of about 350 MB to be safe (using New Simple Volume option) in FAT32 format, which holds the boot files. The secondary partition, which contains Windows operating system files, has to be formatted NTFS. If you are only booting on UEFI based computers, the only thing you would do different from above is to format the drive as GPT partition scheme instead. You can switch between partition schemes easily with this tool, which provides a nice user-friendly interface as well. If you are only booting on BIOS-based PCs, then just convert scheme to MBR and don’t do any partitioning. Then run the WinToUsb program and when you get to the partition selection, just make sure to use the right one for each option. If you are unclear on this, consult the documentation on Easy UEFI. Like I said above, select the same partition for both if booting BIOS. The other option is between a legacy installation and a VHD installation. I don’t know if you are familiar with the difference, but a VHD installation actually puts the Windows operating system files inside a virtual disk container (VHD file), which I may add, can be mounted (while not booted) by just double-clicking on the file if you have a pro version of Windows 10.

To actually boot from the device, you will probably need to modify your BIOS settings. Specific documentation for your system would not be a bad thing, but here is a general guideline: press the appropriate key directly after starting your computer (while the screen is usually still black) to access boot settings, whether it be F9 or F10 or F(other number). On my PC, I can hit ESC and it will bring up the appropriate options. Go to “boot configuration” or “boot options” and first make sure that legacy support is enabled if your computer is UEFI-based and you installed Windows to a “removable” drive. Otherwise, just make sure that the USB option is the “boot first” device. This way, whenever you plug in the device before booting, the system will automatically boot from the USB device. *Important Note: if your PC is UEFI-based and you installed Windows to a “removable” drive, this automatic booting of USB does not work for your device, and you will have to hit the bootloader options every time and manually select the device.

Hope it works, but please don’t chew me out if it doesn’t. It worked well for me. Hint: these handy little devices are awesome if you have to use a computer at work or school and want to use your own operating system on it. The main Easy UEFI program (not WinToUSB) lets you add more than one operating system to the USB drive, and I will include an article about that as soon as I test it myself. If you upgrade to the the paid version of WinToUSB, you can actually clone your current operating system (files, drivers, programs, the whole thing) on your PC to the USB device and boot it from almost anywhere. Now THAT is cool.