Infocom game module for Z-machine version 5
File type: Game file
A .z5 file extension identifies an Infocom game module containing Z-machine instructions for version 5 of the virtual machine.
The file is a Z-code story file and can be opened with a suitable interpreter such as Frotz for Microsoft Windows.
Found 2 different file type records with the same z5 filename suffix.
File type category:
Game file
Date updated: October 30, 2026
The .z5 file extension is associated with Infocom and is used for files containing Z-machine instructions, also called story files or Z-code files. The file contains the program and game data that an interpreter uses to run an interactive fiction game.
Z-code files commonly use extensions ending in .z1, .z2, .z3, .z4, .z5, .z6, .z7 or .z8. The number identifies the Z-machine version for which the file is intended. Z-code files occasionally use the .dat extension. Types 1, 2, 4, 6 and 7 are extremely uncommon; types 3, 5 and 8 are the most common. Type 6 provides some graphics support.
Interpreters for Z-code files are available on a wide range of platforms, including older systems such as the Apple II, TRS-80 and Sinclair computers, portable systems such as Palm OS devices and the Nintendo Game Boy, and most modern platforms. The format is a legacy game format, but remains supported by interpreters such as Frotz.
Install Frotz for Microsoft Windows and open the .z5 file with it. Frotz interprets the Z-machine instructions and runs the Infocom game contained in the file.
Other Z-code interpreters are available for many older, portable and modern platforms. If the file does not open automatically, select the interpreter's open command and choose the .z5 file.
A .z5 file is normally used directly with a Z-machine interpreter rather than converted to another format. Renaming its extension does not convert the game and may prevent an interpreter from recognising it.
To preserve or distribute the game, keep the original story file and use an interpreter such as Frotz. A playable conversion to a different game system generally requires a separate port or rewrite rather than a simple file conversion.
Software applications that handle other tasks involving z5 files:
Microsoft Windows
File type category:
Various data file
Date updated: November 4, 2011
The Z5 file extension is associated with ZoneAlarm, a personal firewall software, originally created by Zone Labs and currently developed by CheckPoint Software Technologies LTD.
One of ZoneAlarm features is MailSafe, which detects e-mail attachments and warns the user about their presence. When a potentially dangerous attachment is detected, the program quarantines the file with simple renaming of its original file extension, so it breaks the common program association function in Windows and prevents such files from being executed (or launched via associated program).
A file with Z5 file extension had its original file extension renamed for security reasons.
Software applications that handle other tasks involving z5 files:
Microsoft Windows
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