.C4F file extension

To open .C4F files on Windows, install and use a Clonk/ClonkRage-compatible setup and try opening the .C4F from within the game/tools (it is a Clonk group file used for scenario data).

To open a .C4F file, use a Clonk/ClonkRage-compatible game installation or tools that can read Clonk “group” files (application/vnd.clonk.c4group). If you’re on mobile, you will usually need to transfer the file to a desktop system to open or inspect it.

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Last updated: April 29, 2026 · Reviewed by Julian Stricker

Open on your device

Choose your operating system for a dedicated step-by-step opening guide.

How to open .C4F files

Use these platform-specific instructions to open .C4F files safely.

Windows

Install and use a Clonk/ClonkRage-compatible setup and try opening the .C4F from within the game/tools (it is a Clonk group file used for scenario data).
If double-clicking does not work, right-click the file → “Open with…” and select the Clonk-related application that handles group files.
If you only need to identify what it is, check whether your system recognizes it as application/vnd.clonk.c4group (it is registered for .c4f and related extensions).

Full Windows guide

Mac

If you have a Clonk/ClonkRage-compatible application installed, try opening the .C4F from within that application (it is a Clonk group/scenario container).
If Finder cannot open it, use “Open With…” and choose the Clonk-related app (macOS typically will not have a native viewer for this format).
If no compatible app is available on your Mac, transfer the file to a system where you can run Clonk tools to inspect/extract its contents.

Full Mac guide

Linux

Try opening the .C4F with Clonk-related tools available on your system (the format is a Clonk “group file” used for scenarios).
If your file manager prompts for an application, choose a Clonk/ClonkRage-compatible program rather than a generic text editor.
If you need format association, note that Debian’s mime.types maps .c4f to application/vnd.clonk.c4group.

Full Linux guide

iOS

iOS typically cannot open .C4F natively; transfer the file to a desktop system with Clonk/ClonkRage tools if you need to view or use the contents.

Full iOS guide

Android

Android typically cannot open .C4F natively; move the file to a desktop system with Clonk/ClonkRage tools to open it as a scenario/group package.

Full Android guide

Security notes

.C4F is a package/container format (a “group file”), so it can bundle multiple resources; treat it like you would treat a downloaded archive from the internet and only open content packages you trust.
Be cautious when importing third-party scenario packages into your game environment: malformed or hostile data can exploit weaknesses in parsers, so prefer content from reputable Clonk community sources.
Do not rely on changing the file extension to determine safety or function; .c4f shares the application/vnd.clonk.c4group type with other Clonk group extensions.

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Can't open this file?

These are the most common causes and fixes when .C4F files fail to open.

Common reasons

The file opens as “unknown” or no app is suggested
Opening shows gibberish or a blank result in a text editor
Scenario or content does not load in the engine
Confusion with other Clonk group extensions (.c4g/.c4d/etc.)

Fix steps

Use a Clonk/ClonkRage-compatible installation or tools to open the file as a group/scenario package.
On Linux, confirm your system’s MIME database recognizes it as application/vnd.clonk.c4group (Debian’s mime.types lists .c4f under that type).

OS-specific troubleshooting

What is a .C4F file?

.C4F is part of Clonk’s compressed “group file” system (a package format used for game data). In ClonkRage documentation it is specifically referenced as an “Image Scenario Folder (c4f)”, and the engine searches such parent folders when loading scenarios. The extension is associated with the registered MIME type application/vnd.clonk.c4group (also used by related extensions like .c4g and .c4d).

Background

In the Clonk game ecosystem, many deliverables (game data, scenarios, and related content) are distributed as “group files”—compressed packages that behave like folders to the engine. Wikipedia notes that Clonk release packages are usually packed inside group files such as .c4f/.c4g/.c4d, which is why you often encounter .c4f when downloading or exchanging Clonk content.

ClonkRage documentation calls .c4f an “Image Scenario Folder”, indicating it commonly acts as a container holding a scenario’s resources. The scenario documentation also indicates that the engine searches in parent folders with the .c4f extension, which explains why these files can be important for organizing and loading scenarios.

Because .c4f is a package/archive-like format, opening it “correctly” usually means using Clonk/ClonkRage tooling or the engine so that the contents are interpreted as intended. For troubleshooting or inspection, it is often treated as a group container rather than a single document.

Common MIME types: application/vnd.clonk.c4group

Common .C4F issues

The file opens as “unknown” or no app is suggested

.C4F is a specialized Clonk group/scenario package and many systems do not have an associated default app.

Use a Clonk/ClonkRage-compatible installation or tools to open the file as a group/scenario package.
On Linux, confirm your system’s MIME database recognizes it as application/vnd.clonk.c4group (Debian’s mime.types lists .c4f under that type).

Opening shows gibberish or a blank result in a text editor

.C4F is a compressed group container, not a plain-text document, so text editors will not display meaningful content.

Open the file with Clonk/ClonkRage tools or the game engine that understands group files.
If you need to inspect contents, treat it as a package/archive to be explored with appropriate Clonk tooling rather than a document.

Scenario or content does not load in the engine

Clonk scenarios may rely on folder structure and parent .c4f containers; missing or misplaced packages can prevent loading.

Verify the .C4F file is in the expected location for your Clonk installation/content directory (it may be a parent folder the engine searches).
Re-download or re-copy the file to ensure it was transferred completely (group files can fail if truncated).

Confusion with other Clonk group extensions (.c4g/.c4d/etc.)

Multiple Clonk group formats share the same MIME type and are used for different kinds of content packages.

Check what you downloaded: .c4f is commonly an Image Scenario Folder; other extensions may represent different package types within the same group-file system.
Do not rename the extension to “convert” it; use the appropriate Clonk tools/workflow for the content type.

FAQ

What is a .C4F file used for in Clonk?

In ClonkRage documentation it is an “Image Scenario Folder (c4f)”, i.e., a group/package used to store scenario-related resources that the engine can search and load.

Is .C4F the same as .C4G or .C4D?

They are related: multiple Clonk “group file” extensions (including .c4g, .c4d, and .c4f) are associated with the same registered media type application/vnd.clonk.c4group, but they are commonly used for different kinds of Clonk packages.

Can I open .C4F on iPhone or Android?

Usually not directly. Mobile OSes typically lack common apps for Clonk group files; transfer the file to a desktop system with Clonk/ClonkRage tools to open or inspect it.

Should I rename .C4F to another extension to open it?

No. Renaming does not convert the file and may make it harder for tools to recognize it; use Clonk-compatible software that supports group files.

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