How to Install Ubuntu on a USB Flash Drive
Create a bootable USB thumb drive with [Ubuntu](http://www.ubuntu.com) to install the Debian-based operating system seamlessly alongside Windows 7 or 8.1, or just boot the OS to test its capabilities. That's right -- **you can run Ubuntu directly from the bootable USB drive without installing it**. To create the drive, you can use the [Universal USB Installer](http://www.pendrivelinux.com/universal-usb-installer-easy-as-1-2-3) or the [UNetbootin](http://unetbootin.sourceforge.net) software. **Your computer's BIOS must be able to boot from USB to install or run Ubuntu from a flash drive**.
Open the **[Universal USB Installer](http://www.pendrivelinux.com/universal-usb-installer-easy-as-1-2-3)** page and click the "Download UUI" button to download the utility. Save the file on your hard drive.
Open the **[Download Ubuntu Desktop](http://www.ubuntu.com/download/desktop)** page and select which version of Ubuntu you wish to install on the USB drive. The **Long Term Support** -- LTS -- version offers 5 years of free updates, while the **latest version** of the OS offers just 9 months of free updates.Select the architecture from the "**Choose your flavor**" box. If your system has less than 2GB of RAM, choose "32-bit." Click "**Download**."
Click the "**Not now, take me to the download**" link if you don't want to donate and proceed to the download. *The size of the file exceeds 1GB; ensure you have enough free disk space to save it*.
Plug in the USB flash drive -- with at least 2GB of space -- into a free USB port and then double-click the "Universal USB Installer" file you downloaded earlier to launch the utility. Click "**I Agree**" if you agree to the terms of the License Agreement.
Select "**Ubuntu** from the "**Step 1**" drop-down menu. The software can be used to install many other Linux-based operating systems.
Click the "**Browse**" button in the Step 2 section, select the Ubuntu setup file and click "**Open**." The full path is displayed in the field.
Select the USB flash drive from the "**Step 3**" drop-down box. If the utility doesn't detect the drive, you may check the "Show all Drives" box to view all drives. **Be careful -- selecting the wrong drive may lead to serious loss of data**.To format the drive -- *and erase everything on it* -- before installing Ubuntu, check the "Format Drive" box. The utility formats the drive as Fat32.If you want to run Ubuntu from the USB flash drive and install apps or make changes, **set a persistent file size** using the slider in the Step 4 section. Ubuntu uses this disk space to store everything from new apps to customizations.Click "**Create**" to start installing Ubuntu on your USB thumb drive. Click "Yes" to confirm.
Click "**Close**" after you see the "Installation done, process is complete" message to close the Universal USB Installer utility.Restart your computer, enter BIOS -- by pressing Delete, F2, F10 or Esc -- and **[set the USB drive as the first boot device](http://www.pandasecurity.com/usa/homeusers/support/card?id=950011)**. The computer restarts after you save the changes and exit BIOS.Select "**Try Ubuntu**" from the startup screen to run Ubuntu from the pen drive without installing it. To install Ubuntu, select "**Install Ubuntu**." There is a performance penalty for running Ubuntu from the USB drive instead of installing it on the hard drive. *You can choose to install Ubuntu after you run it -- there is an Install Ubuntu icon in the Unity launcher*.
Tips & Warnings
- Both Universal USB Installer and UNetbootin work almost the same, so the procedures are similar regardless of the product you choose.
- If you prefer to download Ubuntu using a BitTorrent client, click the "Alternative downloads and torrents" link below the Download button. Downloading the file using BitTorrent is usually faster.
- Avoid plugging the USB drive into a USB hub; plug it into a free USB port on the back of the computer, if possible.
- You don't need to format the flash drive before installing Ubuntu on it; the Universal USB Installer can format it for you.
- Don't remove the USB flash drive from the USB port and don't shut down the computer while Universal USB Installer installs Ubuntu on the pen drive.
- Even if the progress bar doesn't move in Universal USB Installer, be patient and don't close the utility.
- Back up important files from the USB flash drive before you begin installing Ubuntu on it. Universal USB Installer may format the drive during the setup procedures and erase everything on it.