Software & Apps File Types What Is an ACF File? How to Open, Edit, & Convert ACF By Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated December 13, 2019 File Types Design Cryptocurrency MS Office Windows Linux Google Drive Apps File Types Backup & Utilities View More Tweet Share Email A file with the ACF file extension is most likely an Adobe Custom Filter file, a format that stores values that are to be used in Adobe Photoshop for manipulating the pixels that exist around a specific pixel. Other ACF files may instead be used with the Steam video game distribution platform as an application cache file used to store information about downloads and updates. If your ACF file isn't in either of these formats, it may instead be an X-Plane Aircraft file or an Agent Character Data file. A less common use for an ACF file is as an Application Configuration file used in Microsoft Visual Studio, a format that holds certain attributes for an application. An even less common use for the ACF extension is a format used by Inmagic DB/TextWorks. ACF also stands for Advanced Custom Fields, a plugin used with WordPress websites. How to Open an ACF File Your ACF file is most likely used with Adobe Photoshop, but only if it's an Adobe Custom Filter file. To open an ACF file in Photoshop, go to the Filter > Other > Custom menu and select the Load button. If your specific ACF file is used with Steam, you may be able to open it as a text document using a simple text editor like Notepad++. If not, try the GCFScape utility from Nem's Tools to open or extract any files out of the ACF file. This format is used in the most recent version of Steam, while GCF and NCF files were used in older versions of the software. X-Plane is a flight simulator that uses ACF files for storing aircraft properties like the plane's limits and engine power. If you're using a version of X-Plane newer than version 9, then your ACF file is most likely a text file (others are in binary), meaning you could also open it in a text editor. You can read more about this format on the X-Plane Developer website. Agent Character Data files that use the ACF file extension are associated with the now discontinued Microsoft Agent animation software. They're used to describe a character and are saved with Agent Character Animation (ACA) files. Microsoft Agent Character Editor may be able to open these types of ACF files. An Application Configuration File also uses the .ACF file extension and should be usable with Visual Studio. If none of these applications can open your ACF file, you might try Inmagic DB/TextWorks. If you find that an application on your PC does try to open the ACF file but it's the wrong application or if you would rather have another installed program open ACF files, see our How to Change the Default Program for a Specific File Extension guide for making that change in Windows. How to Convert an ACF File Converting an ACF file depends entirely on what the ACF file is used for (i.e., what format it's in). For example, you may be able to save an X-Plane Aircraft file to a new text-based format, but Adobe Photoshop's ACF file probably can't be used under any other format. The best thing to do if you want to try to convert your ACF file is to open it in the program that uses it, and then try to find a File > Save As or Export menu. Most file formats, especially the more popular ones like PDF and DOCX, can be converted using a free file converter, but I don't believe this is the case for any format I'm aware of that uses the ACF extension.