How to open a .sit file (Windows, Mac, Linux)

Q: Why can't I open my .sit file?

Usually your computer lacks an app that understands StuffIt. Install one of the apps listed here, or convert the file to a more common format.

A .sit file is a StuffIt Compressed Archive. If double-clicking does nothing, your computer simply does not have an app that reads StuffIt yet. Here is how to fix that on each operating system, using free software wherever possible.

Open a .sit file step by step

Confirm the file really is a .sit. Drop it into the WhatFileType file identifier, which reads its signature without uploading anything.
On Windows, open it with StuffIt Expander for Windows or 7-Zip (some classic .sit).
On Mac, use StuffIt Expander or The Unarchiver.
On Linux, try The Unarchiver (unar).
Still stuck? Convert the .sit to zip, which opens more widely.

Best apps to open .sit files

Windows

StuffIt Expander for Windows
7-Zip (some classic .sit)

macOS

StuffIt Expander
The Unarchiver

Linux

The Unarchiver (unar)

Before you open it: Safe as an archive; the risk profile is its contents, exactly like ZIP. Old Mac software inside may simply no longer run on current systems.

Frequently asked questions

Why can't I open my .sit file?

Almost always because no installed app understands StuffIt. Install one of the apps above, or convert the file to a format your existing software already reads.

How do I open a .sit file on a modern computer?

Install the free StuffIt Expander (macOS or Windows) or try The Unarchiver. Both open classic .sit archives; Expander is the safest bet for odd or old variants.

What is the difference between .sit and .sitx?

.sit is the classic StuffIt format from the Mac OS 8/9 era; .sitx is the redesigned StuffIt X format from 2002 with better compression but even less third-party support.