Nearly all open windows in a GUI (graphical user interface) have resizing options. Maximize allows the user to enlarge a window, usually making it fill the entire screen or the program window in which it is contained.
When a window is maximized, it cannot be moved until it is reduced in size using the Restore button. Often, you can get this effect by clicking the same button you used to maximize the window or by double-clicking the title bar.
What does the maximize button look like?
As shown in the picture below, in Microsoft Windows 95 and above, the maximize button (also known as a maximize box) is displayed by a single box in the top-right of the window.
Helpful maximize tips
Tip: Users with a Microsoft Windows keyboard can press Windows key + up or down arrow keys to resize a window.
Tip: To maximize the current window press Alt+Spacebar. Once the window properties drop-down menu is displayed, press X to maximize the window.
Note: You cannot resize a window if it is maximized.
Note: The maximize button will not be available or become a resize button if the window is already fullscreen.
Why can I not maximize a window?
Not all windows can be maximized. If none of the above steps help with maximizing a window or the maximize button is not available the window cannot be maximized.
Maximize for Apple users
With Apple macOS, the maximize button is represented as a yellow button found in the top-left corner of the window. If this button is missing, the program does not support a maximized window. The picture shows the red, yellow, and green circle on a window that has all three options.
How do I maximize a minimized window?
When a maximized program window is minimized, it is hidden from view. To restore the window click the program's icon on the Windows Taskbar at the bottom of the screen on Microsoft Windows computers or on the Dock on Apple computers using macOS.
Tip: You can also use the keyboard shortcut key Alt+Tab that switches between windows in Microsoft Windows to restore a minimized window.
Windows 3.1 and 3.11 maximize
Microsoft Windows 3.1 and 3.11 had an up arrow in the top-right corner of the window for the maximize option as shown in the picture to the right. When clicking the up arrow, the window would become maximized and clicking the down arrow would restore the maximized window back to a window. Clicking the down arrow again would minimize the window.