.ISO File Extension

ISO files are saved in an uncompressed format based on the ISO-9660 file system standard for optical disc media (hence the .iso file extension and "Disc Image" file type). The files are archives that store all the data from a disk image, including the filesystem information, such as directory structures, file attributes, and boot code. Additionally, ISO files are typically large since they store a lot of data.

Before streaming media, many computer users extracted, copied, and burned ISO files from and to optical discs, such as CDs and DVDs, to copy, share, or back up their contents. ISO files store a sector-by-sector copy of every bit of data exactly from the disc, which is different than copying all files from a disc because the disc header information is lost in the copy process.

Users may also download ISO files from the Internet when installing new software or operating systems since an ISO file contains all the necessary information for installation. For example, you can download an ISO file from Microsoft.com to create a bootable installation media, such as a USB flash drive, or to create a virtual machine running Windows 11.

You can open ISO files in various ways, including mounting an ISO file and extracting files from an ISO file.

Mounting an ISO file

Mounting an ISO file is a software process that makes the folders and files in the ISO file readable by the computer (as if you inserted an actual CD or USB flash drive in the computer). In Windows 8 and later, you can mount an ISO file without third-party software by choosing the file and then selecting Manage → Mount in File Explorer.

In macOS, you can mount an ISO file by double-clicking the file. After clicking the file, the DiskImageMounter utility bundled with macOS verifies the disk image's integrity and mounts it after confirming the disk image.

Extracting an ISO file

You can extract files from an ISO archive to access individual files, such as .BIN or .CFG files. You can use various archive utilities, including Corel WinZip, 7-Zip, and RARLAB WinRAR to extract files from an ISO file.

Burning an ISO file to a disc

While burning ISO files to discs is no longer as common as it once was, you may still want to burn an ISO file to a disc to create a physical backup or share data or media. In Windows 7 and later, you can right-click an ISO file and select Burn Disk Image. You can also burn ISO files to discs with third-party software, such as Roxio Toast and PowerISO.

While converting an ISO file to another format is challenging because information like the disc header gets lost, you can extract the files in an ISO file with an archive utility, then compress it in a new format. For example, you can extract files from an ISO archive with Corel WinZip, then compress them in the following formats:

• .DMG - Apple Disk Image
• .BIN - Binary Disc Image
• .IMG - Disc Image Data File

Arbortext IsoDraw illustrations may also be saved to the .ISOZ compressed format to reduce the document size for sharing over email.

To open an ISO file with PCSX2, you can simply drag and drop the file to the application without mounting the disk image. You can also select CDVD → Iso Selector → Browse, navigate to your file, and click Open. In order to use PCSX2, you must "dump" the Basic Input Output System (BIOS) files from your PS2 console. It is illegal to use BIOS data from other PS2 consoles.

NOTE: Because of their large file size, PS2 ISO game files may be compressed. Compressed ISO files may have a different file extension, such as .7Z, which indicates the type of compression used to reduce the file size.

Dolphin is a cross-platform Nintendo Wii and GameCube emulator that allows gamers to play Wii and GameCube games on their PCs. To play a game in Dolphin, gamers must first acquire that game's .GCM, .GCZ, or ISO file. This file contains an exact copy of the data stored on a physical Wii or GameCube disc.

ISO files that contain GameCube games are typically 1 to 1.4 GB in size, while those that store Wii games are typically about 4.7 GB. Because these files are so large in size, gamers often download and store ISO files as .ZIP or .7Z archives. If you receive an ISO file that is saved as a ZIP or 7Z file, you can use a decompression utility, such as 7-Zip, Corel WinZip, or Apple Archive Utility to extract the ISO file from the archive.

NOTE: It is illegal to download ISO files that contain Wii or GameCube games. You should create ISO files by dumping data from a game disc using a game dumping utility.

You can open a Wii or GameCube ISO file in Dolphin (cross-platform). To do so, select Open from Dolphin's menu bar and then navigate to and open your ISO file.

Various third-party utilities allow gamers to copy (or "dump") the game data stored on a PSP disc to an ISO file. They can then can open the ISO file with a PSP emulator to play the game on their computer or mobile device.

ISO files also serve as convenient backups of PSP games, which can be used to play a game on a PSP even in the event the original game disc is damaged or goes missing. Modders can use ISO decompression utilities (such as 7-Zip or The Unarchiver) to unpack a PSP game and examine or modify its assets.

You can open an ISO file and play the game it contains with several PSP emulators, including:

• PPSSPP (multiplatform)
• RetroArch (multiplatform)
• OpenEmu (Mac)