How to open .CW files on Mac
To open .CW files on Mac, there is no commonly supported native macOS app confirmed by the sources for .cw (CU-Writer) files.
Step-by-step instructions
- There is no commonly supported native macOS app confirmed by the sources for .cw (CU-Writer) files.
- Transfer the .cw file to a Windows PC with CU-Writer installed and open it there.
- If you must work on macOS, ask the sender to export the document from CU-Writer to a more common format first.
Common issues
Windows shows “Choose an app to open this file”
This usually happens when CU-Writer is not installed or the file association for .cw is missing.
- Install CU-Writer for Windows, then try opening the file again.
- Right-click the file → Open with → select CU-Writer; optionally set it as the default for .cw files.
The file is identified as application/prs.cww or has the .cww extension
The IANA registration for application/prs.cww lists both .cw and .cww as associated extensions, so you may see either extension or the MIME type label.
- Try opening it in CU-Writer regardless of whether the extension is .cw or .cww.
- Avoid changing extensions as a “fix”; use CU-Writer to open and then export if you need another format.
The file opens but shows garbled text or missing characters
CU-Writer is a Thai-capable word processor; incorrect fonts/encoding support or opening in non-matching software can lead to unreadable content.
- Open the file in CU-Writer (not a generic editor) to ensure correct rendering.
- If sharing, export from CU-Writer to a more widely supported document format to preserve readability on other systems.
Linux/macOS cannot find an application to open the file
Even if the system can map .cw/.cww to a MIME type, the required application (CU-Writer) is not commonly available on those platforms per the provided sources.
- Move the file to Windows and open it with CU-Writer.
- Ask the sender to export the file from CU-Writer into a more common format.
Security note
.cw/.cww is a document format associated with a specific application (CU-Writer); the main practical risk is opening untrusted files in a complex document parser. Prefer opening unknown files in a controlled environment.