.sit file format opening.

These two should be able to open it:

[Stuffit Expander|http://www.stuffit.com/mac-expander.html]

[The Unarchiver|http://wakaba.c3.cx/s/apps/unarchiver.html]

The .sit format is quite old by now - it's a StuffIt archive, and can only be expanded with a StuffIt product, such as the free StuffIt Expander. It was originally used back in the Mac OS 9 and earlier days, nearly a decade ago. There were some issues with the .sit format on Mac OS X, and it was replaced by the newer .sitx format, which never really caught on since a Unix-based system has no need for another compression format.

If you really need to work with .sit files, go get StuffIt Deluxe. However, I'd strongly suggest that any program that is still making active use of the .sit format is one where the developer knows very little about the Mac platform, and in such a case I would not allow such software on my hard drive. A developer who has no knowledge of the platform they're developing for is not one whose software should be trusted to work properly.

Hi Thomas,

A developer who has no knowledge of the platform they're developing for is not one whose software should be trusted to work properly.

I assume you're referring to Smith Micro, who now own Stuffit? No, they aren't that dense. 🙂 The new versions of Stuffit Deluxe or Stuffit (not ever sure what the cheaper version does different) don't even support creating the original .sit files. It will only create .zip or .sitx. The .sitx format is completely compatible with OS X.

which never really caught on since a Unix-based system has no need for another compression format.

And it really hasn't, mostly for that reason. Which is too bad because Stuffit is better. I've tested both .sitx versus .zip files with a variety of file types, and Stuffit always makes a smaller archive. Usually a lot smaller. Whereas .zip only stores .jpg images (essentially no compression at all), Stuffit gets them down to about 40-60% of their normal size.

I routinely transfer hundreds of megabytes of images to my clients. When I can get it compressed into an 80 MB Stuffit X archive rather than a 150 MB zip file, that's saves a lot of transfer time when my current upload speed is only 1 Mbs.

A developer who has no knowledge of the platform they're developing for is not one whose software should be trusted to work properly.

I assume you're referring to Smith Micro, who now own Stuffit?

No, I'm referring to the developer of whatever graphics software AtomikApple is using that has some content in .sit archives.