.CGM file extension
To open .CGM files on Windows, right-click the .CGM file and choose Open with.
.CGM files are typically opened with software that supports CGM Image File. Use CAD viewers/editors that support this design format. Avoid renaming the extension directly, because renaming does not convert the actual file format.
Last updated: March 17, 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
- Right-click the .CGM file and choose Open with.
- Select a trusted Windows app that supports .CGM files.
Mac
- Control-click the .CGM file and choose Open With.
- Pick a compatible Mac application to open the file.
Linux
- Open the .CGM file from your file manager with Open With.
- Choose an installed Linux app that supports this format.
iOS
- Open the .CGM file from Files and tap Share.
- Send it to a compatible iOS app if Quick Look cannot preview it.
Android
- Open the .CGM file from Files or Downloads.
- Choose a trusted Android app that supports the format.
Security notes
- Only open .CGM files from trusted senders.
- Scan downloaded files before opening them.
- Avoid running embedded scripts or macros unless you trust the source.
Recommended antivirus software
Scan files before opening them. These antivirus tools help protect against malware and viruses.
Avast offers free and premium antivirus software that protects against viruses, malware, ransomware, and phishing. Scan files before opening them to ensure safety.
NortonNorton 360 delivers comprehensive antivirus protection, VPN, and identity theft monitoring. Scan files for threats before opening to keep your device secure.
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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
- .CGM file does not open
Fix steps
- Install or update a compatible application.
- Verify the file came from a trusted source and was fully downloaded.
- Try opening the file in an alternative app on another platform.
OS-specific troubleshooting
What is a .CGM file?
.CGM is a CGM Image File format used for technical drawings, engineering design, and manufacturing workflows. CAD files can include geometry, layers, measurements, and annotation metadata. Common MIME type: image/cgm. If the file does not open, check that you are using a compatible app and a complete, trusted file source.
Common MIME types: image/cgm
Common .CGM issues
.CGM file does not open
This usually means the required app is missing or the .CGM file is incomplete.
- Install or update a compatible application.
- Verify the file came from a trusted source and was fully downloaded.
- Try opening the file in an alternative app on another platform.
FAQ
Can I convert a file by renaming it to .CGM?
No. Renaming changes only the suffix. Use a proper conversion tool or export function.
Is .CGM safe to open?
It can be safe when the file comes from a trusted source and is opened in reputable software.
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