Winini

Win.ini is a legacy configuration file used by Microsoft Windows to store a subset of system-wide and user-specific settings in a plain text INI format. It was widely used in Windows 3.x and remained in use through the Windows 95/98 era, and persisted in later versions for compatibility. The file resides in the Windows directory, typically C:\Windows\win.ini or C:\WINNT\win.ini, and was read by the Windows shell and certain applications during startup or runtime to determine behavior and preferences. It is usually used in conjunction with System.ini as part of an early configuration model that preceded the Windows registry.

Format and structure: Win.ini is organized into sections identified by square-bracketed headings, with lines containing key=value pairs. Common sections might include [windows], [intl], or others introduced by specific software. Because it is a plain text file, its contents can be viewed and edited with any text editor, though improper syntax or invalid keys can cause software to behave unexpectedly.

Usage and legacy: With the advent of the Windows registry in Windows 2000 and later, many settings moved away from win.ini to the registry. Today, win.ini is largely obsolete for system configuration, and Windows itself reads it only for backwards compatibility, while many modern applications ignore it. Some older or niche programs may still use win.ini for storing their own configuration data.

See also: System.ini, Windows registry.