.ANI File Extension

An ANI file is a cursor animation file used by the Windows operating system. It contains a collection of .ICO files that comprise an animated cursor's animation. ANI files are very similar to .CUR (Windows Cursor) files, except that they contain multiple distinct images used for animation.

Windows' default animated cursors, such as its wait and hourglass cursors, are stored in ANI files. These files contain all the still ICO images used to animate a cursor. When Windows shows an animated cursor, it is actually showing all an ANI file's included ICO images in sequence.

Custom Windows desktop themes often include custom animated cursors, stored in custom ANI files. These custom ANI files are structured in the same way as Windows' official ANI files.

NOTE: In March 2007, Microsoft reported a vulnerability in the way Windows handles ANI files that could be used to attack users' systems. This issue, which affected Windows 2000 through Windows Vista, was addressed and fixed in Security Bulletin MS07-017.

Windows users can open ANI files in a number of programs, including RealWorld Cursor Editor, Axialis CursorWorkshop, and IcoFX. Each of those programs allows Windows users to open and edit each of an ANI file's included ICO images. Non-Windows users can open ANI files in Inkscape (cross-platform) but should note that Inkscape will load only the ANI file's first frame.