The .isz file extension refers to Zipped ISO Disk Image files. ISZ files are compressed ISO images created to save disk space. The ISZ file format supports password protection and encryption. Large ISZ files can be split into separate volumes. ISZ files are similar to ISO disk images, but compressed to be smaller. The ISZ file format was created by EZB Systems, developer of UltraISO software.
UltraISO software can open, create and edit .isz files. Other programs like Alcohol 120% also support the .isz file format. ISZ files can be found on any operating system, though support may be limited. Most programs do not natively support .isz files as it is a somewhat rare format.
When an ISZ file is split into parts, the separate files retain the original filename but have different extensions. The first part uses .isz, the second uses .i01, the third .i02, and so on. This allows distribution of large ISZ files over the internet or multiple storage devices. The parts can later be combined to reconstruct the original ISZ file.
To open an .isz file on your computer, double click on it. If you have the correct application set up to handle .isz files, it will open automatically. If not, you may need to download or purchase an ISZ-compatible application such as UltraISO. With the right software, ISZ files can be easily opened just like any other file format.
UltraISO