Open ISZ files in your browser
UltraISO's compressed disc image, an ISO packed in chunks. Open one right here, see every file on the disc and open the ones you need. Nothing leaves your device.
Or drop it anywhere on this page
What you'll see
Your disk opens like a folder, each volume's files listed on the left, with a map of its partitions and what the disk holds beside them.
- A map of the disk • Every partition to scale
- Every volume as a folder • Files open at once
- Verify • SHA-256, SHA-1 or MD5
- Export • Save as ZIP or Extract all
About ISZ
EZB Systems made ISZ for UltraISO, its Windows disc image editor, to keep an ISO smaller: the image is cut into chunks, each packed with zlib or bzip2 or kept as it is, and a run of empty sectors costs nothing. A big one can be split into parts, the .isz first and then .i01, .i02 and on, and EZB published how it works.
Disc images of software, games and installers went around as ISZ, but only UltraISO and a few archivers read it, and nothing on a Mac or a phone does. A locked ISZ is encrypted in a way EZB never wrote down.
Filepeek reads ISZ with a reader of its own, unpacking only the chunks it needs, and opens the disc inside like a folder, each file opening in its own viewer. The disc's ISO is listed beside its files, ready to save, and an encrypted ISZ says so.
Compressed ISO image
.isz
Format
- MIME type
- application/x-isz
- Made by
- EZB Systems
Inside the file
- Holds
- A disc image in chunks
- Compression
- zlib or bzip2
- Parts
- .isz, then .i01, .i02 and on
- Made by
- UltraISO
Opens in every browser
Filepeek opens ISZ with a reader of its own in Chrome, Edge, Firefox and Safari. No browser opens it by itself.
- YouChromeOpens through Filepeek
- YouEdgeOpens through Filepeek
- YouFirefoxOpens through Filepeek
- YouSafariOpens through Filepeek
Apps that open ISZ
- WindowsUltraISO and Bandizip
- MacNo app built in opens it
- iPhone and iPadNo app built in opens it
- AndroidNo app built in opens it
Questions
How do I turn an ISZ into an ISO?
Open it here, then save the .iso listed beside the disc's files. It's the whole disc, which Windows, macOS and Linux mount by themselves.
How do I open an ISZ split into .i01 and .i02 files?
Drop the .isz together with all its .i01, .i02 and later parts. They open as one disc.
Why won't my ISZ open?
It may be encrypted, which UltraISO does with a password in a way it never published, so only UltraISO opens it. Filepeek says so when it is.
What's the difference between ISZ and ISO?
An ISO keeps every sector of a disc as it is. An ISZ packs the same sectors in chunks, so it takes less room, but needs an app to read it.