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.CGM file extension

To open .CGM files on Windows, try opening the .cgm file in the application that produced it (common in technical illustration/enterprise documentation workflows, including SAP-related tooling).

To open a .CGM file, use a CGM-capable viewer or graphics/CAD tool (often found in technical documentation and enterprise workflows, e.g., SAP environments). If your device can’t preview it, open it on a desktop system with CGM support or convert it using a tool that can import CGM.

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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 .CGM files

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

Windows

  1. Try opening the .cgm file in the application that produced it (common in technical illustration/enterprise documentation workflows, including SAP-related tooling).
  2. If it doesn’t open, use the app’s Import/Open feature (rather than double-click) and select CGM/Computer Graphics Metafile if offered.
  3. If you only need to view it, use a CGM-capable viewer on Windows or convert it on a desktop system that supports CGM.
Full Windows guide

Mac

  1. If double-clicking does not work, open your graphics/CAD or technical illustration tool and use File → Open/Import to select the .cgm file.
  2. If you don’t have CGM-capable software on macOS, transfer the file to a desktop environment where CGM is supported in your workflow, then export to a more common sharing format.
Full Mac guide

Linux

  1. In the file manager, try Open With and look for apps associated with “Computer Graphics Metafile” (shared-mime-info identifies .cgm as image/cgm).
  2. If that fails, open it from within a graphics/CAD application that supports CGM import, or convert it using a CGM-aware tool available in your environment.
Full Linux guide

iOS

  1. iOS may not preview CGM reliably; if the Files app can’t display it, send it to a desktop CGM-capable application (or to the system that generated it) to view or export it to a more common format.
Full iOS guide

Android

  1. Android support varies; if your file manager can’t open it, transfer the .cgm to a desktop CGM-capable application or the originating enterprise/technical documentation system to view or convert it.
Full Android guide

Security notes

  • CGM files are graphics metafiles (image/cgm), not executables, but they can be complex to parse; only open CGM files from sources you trust to reduce the risk of exploiting bugs in viewers/importers.
  • Be cautious with CGM files received via email or downloaded from unknown sources, especially if you must open them in older or unmaintained graphics/CAD tools.
  • Prefer viewing/converting in well-maintained software and, when possible, convert to a safer sharing format before distributing broadly to users who may not have CGM-capable tools.

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Can't open this file?

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

Common reasons

  • The file won’t open or shows as an unknown format
  • Opens, but graphics look wrong or elements are missing
  • File extension and MIME/type detection problems

Fix steps

  1. Open the file from inside a CGM-capable application using an Import/Open command (don’t rely on double-click association).
  2. Try opening it in the same environment/workflow that produced it (common in technical illustration and SAP-related documentation workflows).
  3. If you only need to share it, export/convert from a CGM-capable tool to a more widely supported format.

OS-specific troubleshooting

What is a .CGM file?

CGM (Computer Graphics Metafile) is an international standard (ISO/IEC 8632) for platform-independent interchange of 2D graphics. A CGM file can contain vector drawing commands, embedded raster images, and text. On many systems it is recognized by the MIME type image/cgm.

Background

CGM is designed as a standardized “metafile” for exchanging technical graphics across different computers and software. Unlike a simple bitmap-only format, CGM can represent drawings as structured vector instructions as well as raster elements and text, which is useful for engineering and documentation workflows.

The Library of Congress describes CGM as supporting 2D vector/raster/text in a single format family, with the standard published as ISO/IEC 8632. Wikipedia and vendor documentation (e.g., IBM) also describe CGM as an ISO-standard format, and SAP documentation notes CGM’s role as a platform-independent interchange format for technical illustrations.

In practice, whether a .CGM opens smoothly depends on the specific CGM “profile” and features used (some files are simple; others rely on parts of the standard that not all viewers implement). When you can’t open a file, it often means you need a different CGM-capable application or a conversion step to a more common format for sharing.

Common MIME types: image/cgm

Further reading

Authoritative resources for more details on the .CGM format.

Common .CGM issues

The file won’t open or shows as an unknown format

CGM is a specialized ISO standard and many general-purpose image viewers don’t support it. The issue is usually missing CGM support rather than a bad file.

  1. Open the file from inside a CGM-capable application using an Import/Open command (don’t rely on double-click association).
  2. Try opening it in the same environment/workflow that produced it (common in technical illustration and SAP-related documentation workflows).
  3. If you only need to share it, export/convert from a CGM-capable tool to a more widely supported format.

Opens, but graphics look wrong or elements are missing

Different tools may implement different CGM parts/profiles; complex CGM features (mixed vector/raster/text, specific attributes) may not render identically everywhere.

  1. Try a different CGM-capable application (or the original creator tool) to compare rendering.
  2. If you control the export, re-export using a simpler CGM option/profile if available, or export to another interchange format for recipients.

File extension and MIME/type detection problems

Some systems rely on MIME mappings (e.g., image/cgm) and file associations; if misconfigured, the OS won’t know what to do with .cgm files.

  1. Ensure the file really is a CGM and still has the .cgm extension.
  2. On Linux desktops, verify your environment recognizes image/cgm and associate it with your chosen CGM-capable application.
  3. Use the application’s File → Open/Import rather than relying on the OS association.

FAQ

What does .CGM stand for?

CGM stands for Computer Graphics Metafile, an ISO/IEC 8632 standard for 2D graphics interchange (vector, raster, and text).

What is the official MIME type for .cgm files?

The registered media type is image/cgm (IANA).

Why can’t my phone preview a .CGM file?

Mobile platforms often lack built-in CGM viewers. If the device can’t display it, open it on a desktop CGM-capable application or export/convert it from the system that generated it.

Can I convert a file to CGM by renaming the extension to .cgm?

No. Renaming only changes the filename; you must export or convert using software that supports CGM (ISO/IEC 8632).

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