.CHM file extension
To open .CHM files on Windows, right-click the .chm file and choose open with..
.CHM files are typically opened with software that supports CHM Data File. Open with the originating app, text editors, or specialized data tools. Avoid renaming the extension directly, because renaming does not convert the actual file format.
Open on your device
Choose your operating system for a dedicated step-by-step opening guide.
How to open .CHM files
Use these platform-specific instructions to open .CHM files safely.
Windows
- Right-click the .CHM file and choose Open with.
- Select a trusted Windows app that supports .CHM files.
Mac
- Control-click the .CHM file and choose Open With.
- Pick a compatible Mac application to open the file.
Linux
- Open the .CHM file from your file manager with Open With.
- Choose an installed Linux app that supports this format.
iOS
- Open the .CHM file from Files and tap Share.
- Send it to a compatible iOS app if Quick Look cannot preview it.
Android
- Open the .CHM file from Files or Downloads.
- Choose a trusted Android app that supports the format.
Can't open this file?
These are the most common causes and fixes when .CHM files fail to open.
Common reasons
- .CHM 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 .CHM file?
.CHM is a CHM Data File format used for structured application data, imports/exports, and machine-readable workflows. Data formats can store records, key-value structures, schemas, and application state. Common MIME type: chemical/x-chemdraw. If the file does not open, check that you are using a compatible app and a complete, trusted file source.
Common MIME types: chemical/x-chemdraw
Common .CHM issues
.CHM file does not open
This usually means the required app is missing or the .CHM 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.
Security notes
- Only open .CHM files from trusted senders.
- Scan downloaded files before opening them.
- Avoid running embedded scripts or macros unless you trust the source.
FAQ
Can I convert a file by renaming it to .CHM?
No. Renaming changes only the suffix. Use a proper conversion tool or export function.
Is .CHM 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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