Software & Apps File Types What Is a FAT File? How to open or convert FAT files Share Pin Email Print File Types Design Cryptocurrency MS Office Windows Linux Google Drive Apps File Types Backup & Utilities View More 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 18, 2018 A file with the FAT file extension is a Zinf Audio Player Theme file. Inside a FAT file is a collection of images and an XML file that describes how the Zinf audio player should look. FAT files are really just renamed .ZIP files. You can download these free themes in the FAT format from the Zinf website. If what you're really looking for is something about the FAT file system (File Allocation Table), and not a file that ends in the FAT extension, see our What Is File Allocation Table (FAT)? piece for more information. How to Open a FAT File Zinf (it stands for "Zinf Is Not FreeA*p") is the program used to open a FAT file. To do this, go to Options > Themes > Add Theme, browse for the FAT file you want to add to the list of themes, select that theme, and then choose the Apply button. Given that .FAT files are simply .ZIP files, you could also open the file by renaming it to .ZIP. Opening the FAT file this way will show you the XML file and images that it contains, but the theme as a whole of course won't be applied to Zinf - you have to follow the steps above to do that. Another option for opening a FAT file as an archive to see the files inside is to install a free file extractor like 7-Zip and then right-click the FAT file and choose to open it with the file decompressor. If you find that an application on your PC does try to open the FAT file but it's the wrong application or if you would rather have another installed program open FAT files, see our How to Change the Default Program for a Specific File Extension guide for making that change in Windows. How to Convert a FAT File A Zinf Audio Player Theme file needs to exist with a FAT file extension in order for Zinf to properly open the file and apply the theme, so we see no reason to want to convert this file to any other format. However, since the FAT file is really a ZIP archive, you could convert it to another archive format, but again, saving the FAT file as a 7Z or RAR file will do you no good but to open the file as an archive since the file extension needs to be .FAT in order for Zinf to use it. Remember what we said about changing the .FAT extension to .ZIP. Doing that doesn't convert the file to the ZIP format because the FAT file is already a renamed ZIP file. All renaming the extension does is associate the FAT file with a different program (like a file extractor tool). A file converter tool is what's used to actually convert one file format to another, and not just rename the file extension. Still Can't Open the File? The FAT file extension is similar to the extensions used for FAX and FFA (Find Fast Status) files. If your FAT file doesn't open with Zinf, it's possible you're misreading what extension is affixed to the end of the file.