Opening a JWW file on a Mac
Jw_cad is a Windows-only program, so a Mac has nothing installed that can open a .jww. Here are four ways around it, in order. The easiest is to convert the file in your browser.
Why it will not open
Jw_cad was written for Windows and there is no official Mac version. On top of that, .jww is Jw_cad's own save format rather than a format meant for moving data between programs, so macOS has nothing registered to handle the extension. That is why double-clicking does nothing, or shows a "cannot be opened" message. The file is not damaged and the download did not fail.
Four ways around it
Convert it in the browser (easiest)
Open this site in Safari or Chrome and pick the file. Nothing to install, no sign-up. The drawing is processed inside your own Mac and is never sent anywhere. If you only need to look at it, put it in a document, or print it, this is enough.
Run Windows inside the Mac
Virtualization software such as Parallels lets you run Windows on the Mac and install the real Jw_cad. This is the option for people who need to edit drawings. It costs a Windows licence and takes time to set up.
Use the unofficial Mac build
There is a community port called Jw_cad for Mac. It is free to try, but it is not official software. The first time you open it macOS blocks it with "cannot be opened because the developer cannot be verified", so you have to right-click and choose Open. Nothing about it is guaranteed, so always keep the original file.
Ask the sender for a PDF
If you only need to read the drawing, this is the most reliable answer. They already have Jw_cad open, and exporting a PDF takes seconds. Asking once is often faster than converting every file they send.
Doing it in the browser, step by step
- Save the attachment to the Mac first. The Downloads folder is fine.
- Open this site in Safari or Chrome.
- Drag the .jww onto the upload area, or click to choose it. The drawing appears straight away.
- Pick a format and download. PDF to print or share, PNG or SVG to put in a document.
What opens the result on a Mac
- PDF and PNG open in Preview, which is already installed. Nothing else needed.
- SVG also opens in Preview, as well as Illustrator and Affinity Designer, and stays sharp however far you zoom in.
- DXF opens in Mac CAD applications. Lines and text arrive as real geometry, so you can keep editing.
Worth knowing
- The drawing is processed inside your Mac only. Nothing is sent to a server, so this is usable for a client's drawings.
- A very large drawing can take a while. The limit is your Mac's memory rather than the converter.
- Conversion runs one way. There is no way back from PDF or DXF to .jww.
- This site views, converts, and marks up drawings. It is not a drafting program — redrawing the drawing itself still needs Jw_cad.