What is ICNS File Format

icns file format

An .ICNS file contains an icon used by Mac OS X applications. It is sometimes called Apple Icon Resource File.

The .ICNS file format is a container that stores one or more images, supports 1-bit and 8-bit alpha channels and multiple image states.

Icon images can be of 16 x 16, 32 x 32, 48 x 48, 128 x 128, 256 x 256, 512 x 512 and 1024 x 1024 pixels (as of Mac OS X 10.8 Mountain lion). Image states include open, closed, and more.

.ICNS files are usually located in the Contents/Resources folder within the application package. They are referenced via the application’s Mac OS X Property List (.PLIST) file.

Icon images can be scaled by the operating system to adjust to the necessary display size. The larger icon images are usually in the JPEG 2000 or the PNG file format. An .ICNS file may be both compressed and uncompressed.

The structure of an ICNS file consists of a header and the binary icon data. The header consists of 8 bytes of data, four with the Magic literal, and four with the length of the file. The icon data section stores the type and size of each icon image, followed by the binary image data. The size of the binary section varies according to the image size.

There are many types of icon images, each usually identified by a four-character name. Examples are: ICON, icm4, icm8, ics4, etc. An .ICNS file can be converted into other formats using Inkscape or XnView (for Windows users) and Snap Converter (for Mac users). There are also other applications that can convert .INCS files, for both the Windows and the Mac environments.

An .ICNS file can be created from a PNG file using the Icon Composer program available within the Apple Developer Tools suite. This tool set is aimed at developers of applications for Apple computers. An .ICNS file format is a similar counterpart to an ICO file format for Windows icons.

How to Open ICNS Files

There are several tools that can open .ICNS files. Amongst them are:


  • Axialis IconWorkshop
  • IcoFX
  • XnView
  • Inkscape

MacOS X:

  • Apple Preview
  • Icon Machine
  • Folder Icon X
  • Adobe Photoshop (must have the IconBuilder plug-in installed)

How to Recover Deleted ICNS Files

Managing so much digital information is not easy. Sometimes, unintentionally you may delete an .ICNS file. However, it is good to know that an .ICNS file deletion only removes a reference to the content. The data remains intact.

Based on this fact, Disk Drill, a data recovery application developed by Cleverfiles, uses some powerful algorithms, which repair and rebuild the .ICNS file. Sometimes, the program can’t find the original name, and assigns a generic name to the recovered data. A generic name has the form file001.icns.

Disk Drill can recover ICNS files from many different devices, such as internal and external hard drives, USB based drives, memory cards and more.

Disk Drill is available for free!

Disk Drill
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Steps for Recovering ICNS Files Successfully

After downloading the Disk Drill’s installer, you must do the following:

  1. Install Disk Drill by clicking on the installer’s icon. The program will provide you with a set of easy instructions. Just follow them.

  2. Open Disk Drill by clicking on the app’s icon. Disk Drill will automatically detect all connected digital devices. Select the one that contains your .ICNS file(s).

    Disk Drill also lets you recover ICNS files from an image copy. Image files are a bit-by-bit copy of a digital device. Therefore, they are an exact replica of the original, which contains all deletions. They are used in Digital Forensics, as they let the analyst perform an ICNS file recovery, while keeping the original legal evidence intact. You just need to attach your image file, and do your ICNS recovery in the same manner as with any other device.

  3. Narrow the search down by selecting the .ICNS file extension. This will result in a faster and more efficient ICNS file recovery.

  4. Start the scan of the selected device. Disk Drill lets you pause or cancel the scan at any time. It also lets you save the ICNS file recovery session, and continue later on without any loss of work. This option is useful when your device is of a large size, as in this case the scan may take several hours.

  5. Once the scan is completed, Disk Drill presents the results in a list. This list can be narrowed down by using the filters by date or size provided by the program.

  6. Select the .ICNS file(s) and retrieve it (them) to a folder of your choice.

You have successfully completed your ICNS recovery!

recover deleted icns

Arthur Cole

Arthur Cole is a freelance content creator. He also has a more than 10-year experience in program development for macOS, Windows, iOS, Android.Arthur Cole is a writer with deep expertise in programming, who can easily...

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Approved by
Brett Johnson

This article has been approved by Brett Johnson, Data Recovery Engineer at ACE Data Recovery. Brett has a Bachelor's Degree in Computer Systems and Network, 12 years of experience.