File Extension ACO

  • Full name
    Adobe Photoshop Color Palette And Swatches Format
  • Developer
    Adobe Systems
  • Popularity
Have you encountered a problem with a ACO file? Don’t you know which program opens a file with this extension? You will find all the information you need about working with a ACO file here. In the further part of this page we have added a list of programs that should open your ACO file. It is enough you choose a proper application for your operating system, download and install it.


The file extension acb is used by the image editing software Adobe Photoshop for so-called Color Swatches files. In these color palettes are stored. These consist of a collection of color codes, names and color space specifications such as RGB, LAB or CMYK.

ACO Color palette files are used, for example, in image editing to save color palettes for reuse or to match a particular color standard. Depending on the intended use of the image (screen, print, etc.), certain color catalogs are better suited than others.

You can access the color palettes in Photoshop by clicking on the small arrow in the Swatches window. Photoshop already offers a number of different libraries included, including ANPA, FOCOLTONE, PANTONE and TRUMATCH.

With such ACO color files, colors of an image can also be saved as a color palette. In addition, there are thematically sorted ACO files on the Internet for download. To be able to use your own ACO file, you have to save it under 'Preferences / Swatches' in the Photoshop program folder.

Programs which can open a ACO file

How to open a ACO file? Advice and guidance

Absolutely most often appearing reason that prevents you from opening the ACO file is the lack of a proper application to support it in your operating system. It is notably the first thing you need to address. When one of the programs to support a ACO file from the list is already installed, you can try to rerun the file. The system should display a message asking you to choose a primary application to support ACO files. At this point we are looking for disk space where the application was installed in and we can link it with a ACO file. Since then, our operating system will use the selected program to support all ACO files.

Other issues

Despite the described problem with ACO there may be many more problems. If the existing operations were not effective, get involved with the following matters:

- verify that the ACO file is not damaged and that it has been downloaded or copied in whole
- verify that the file has a file extension that has not been intentionally changed (for example, if it do not contain other information than its extension suggests)
- make sure again whether the ACO file type is linked in the operating system with a proper program
- make sure that the file is not infected with a virus and you have up to date software and drivers.

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