Q4OS for Windows setup, user manual, rev. 04/2026

Q4OS for Windows setup

user manual

1. Introduction

The Windows installer enables you to install Q4OS alongside Windows in an easy way, without modifying your existing Windows operating system, nor any of your installed software. Q4OS is installed within Windows as a standard application, no separate disk partitions, just a folder in the Windows filesystem. Once installed, you will be able to switch back and forth between Windows and Q4OS each time you restart your computer. This installer is compatible with Windows 11, 10, 8 or 7 versions, and it seamlessly supports Secure boot if available in the PC firmware.

If your Windows becomes lagging, it's the right time to try Q4OS out, a lightweight, snappy and easy to use operating system with variety of applications available in repositories. Q4OS is not intended to be a replacement, but the perfect complement to an existing Windows installation.

2. Installation

At first, you need to get setup executable, so download file "q4os-winsetup.zip" from downloads section of the Q4OS website. After downloading, unzip the file and launch it in the usual way by double clicking it in Windows file explorer. During the installation process, keep the file explorer window open and pointed to the unzipped folder so that the installer can access the required temporary files.



On Windows 11/10, depending on the security policy of your system, a popup window titled "Windows protected your PC" may appear when trying to execute the installer. You only need to click "More info" and confirm the Q4OS setup is safe to continue.



In the User Account Control UAC window, click Yes and the Q4OS setup window will now appear. Follow the instructions of the guide style installer. You will be asked to choose the storage space, this means how much storage you would like to assign for Q4OS in your Windows's drive.



The installer will start downloading, extracting and expanding the target image file. This process may take some time, so please be patient. Once the installation is complete, close the installer window and restart your computer.

Automatic post-installation steps take place at the first boot in text mode. These steps can take from a few seconds to several minutes, depending on the selected disk size. On the first reboot, Q4OS loads directly without displaying the Windows entry. This is expected behavior, so please do not worry, simply allow the first boot process to complete. Do not interrupt any running tasks and wait for the installer to finish its operations. Once the process is complete, the system will be fully set up and ready to run either Windows or Q4OS, selectable from the boot menu.

3. Boot menu

You will be allowed to select either Windows or Q4OS entry at boot time, as the installer registers Q4OS entry into the UEFI boot menu. However on some computers, firmware forces the Windows bootloader to be the only in the boot list, which means by default, you won't see Q4OS entry when you boot your computer. Your computer will instead continue to boot into Windows and it will appear, that nothing has in fact happened. To boot into Q4OS, restart computer and press the function key to pull up the boot menu. The following list provides the function keys for common computer manufacturers:

 Acer - Esc, F9, F12
 ASUS - Esc, F8
 Compaq - Esc, F9
 Dell - F12
 EMachines - F12
 HP - Esc, F9
 Intel - F10
 Lenovo - F8, F10, F12
 NEC - F5
 Packard Bell - F8
 Samsung - Esc, F12
 Sony - F11, F12
 Toshiba - F12

You need to tap the function key straight away and before Windows boots. This will bring up a menu and you can choose to boot either Windows or Q4OS. If you choose Q4OS from this menu, then Q4OS will load and you can begin using and enjoying it.

If Q4OS doesn't start when selected from the boot menu, you would need to enter BIOS setup and switch the Secure boot mode to Audit mode instead of Deployed mode. Another way to make Q4OS bootable would be to turn the Secure boot off.

4. Tips

4.1. Make Q4OS the default boot entry instead of Windows https://www.q4os.org/forum/viewtopic.php?id=5953

4.2. Expand root filesystem disk size https://www.q4os.org/forum/viewtopic.php?id=3805, https://www.q4os.org/forum/viewtopic.php?id=5933

4.3. Access data and filesystem in the loopfile https://www.q4os.org/forum/viewtopic.php?id=3805

4.4. Bitlocker encrypted drives are not currently supported. To proceed with the Q4OS for Windows setup, you must first switch off Bitlocker encryption on the target drive.

5. Uninstallation

Uninstalling Q4OS is a simple matter of running the downloaded executable again, which will prompt you to uninstall the existing Q4OS operating system. Just launch the "q4os-winsetup.exe" installer again and the uninstall wizard starts.



The uninstaller wipes out Q4OS completely. Uninstallation is quick and simple, and leaves no remnants or abandoned files.

Q4OS for Windows setup, user manual, rev. 04/2026