SIT File Extension

StuffIt Archive

File Type sit
Developer Smith Micro
Popularity
4.8 (41 vote)
Application StuffIt Deluxe
Category Compressed Files

What is a SIT file?

Files with the SIT extension are specifically tied to StuffIt Archive, a Compressed Files type, and there are 820 files in this category.

The StuffIt Archive (SIT) was created by Smith Micro, a company that developed file format and produced 7 programs for their use.

SIT files are supported by Mac OS and Windows. If you need to extract a SIT file, you can use one of 4 programs, such as StuffIt Deluxe, StuffIt and StuffIt Expander.

MIME types

application/x-sit
application/x-stuffit

File Signature

HEX code: 53 74 75 66 66 49 74 20 28 63 29 31 39 39 37 2D. ASCII code: SIT!.

Windows

Mac OS

How to open a SIT file?

If you’re having difficulty opening a SIT file, it is often due to not having the correct software. To solve the problem, choose a compatible program from the list. Then follow the link to the official developer site, download the software, and install it on your device.

StuffIt Deluxe, StuffIt and StuffIt Expander stand out as the preferred programs to manage SIT files effectively. To install the latest version of StuffIt Deluxe on your computer, visit the Smith Micro website where you can download the version available for all operating systems.

After installation, your operating system should automatically open SIT files with StuffIt Deluxe.

Set StuffIt Deluxe as the default SIT handler

Choose an app to open a file on Mac

Right click or use Control + left click on the desired SIT file to launch the file options menu;
Choose "Open in Application" and click "Other";
Next, at the bottom of the window, you will see the "Enable" menu, in which "Recommended Programs" is selected by default;
In this menu, select "All Programs", then find StuffIt Deluxe and check the box next to "Always open in the application."

Set default programs for Windows

Start by right-clicking on your SIT file, then select "Open With" and continue by clicking "Choose another app" from the options provided;
In the pop-up window, find and select the StuffIt Deluxe application from the available options;
Make sure the "Always use this app" checkbox is checked and click "OK" to confirm your choice as the default app for opening SIT files.

Effective solutions for SIT file problems

There are some common issues with SIT files that can be resolved easily by making minor adjustments to your software. Below, you’ll find these issues along with practical troubleshooting tips.

What are the methods to detect if my SIT file has been corrupted?

SIT compressed files that have become corrupted may display one or more of the following symptoms:

An unexplained increase in the size of the SIT file;
Trying to work with the archive in StuffIt Deluxe or other programs causes instability or program crashes;
The file does not open correctly or displays error messages;
While working with the file, error alerts are encountered;
The file exhibits poor performance during editing operations in StuffIt Deluxe;

Why does StuffIt Deluxe crash?

Insufficient software updates can contribute to StuffIt Deluxe crash. To avoid this, make sure that you have installed the latest updates for Smith Micro products.

Restarting your computer can resolve numerous common problems, so it should be the initial step before changing any software-related settings.

How to repair a corrupted SIT file?

Open the damaged SIT file in a recovery program and select the "Repair" menu item to start the repair operation. Please wait patiently for the recovery process to finish as it will automatically repair the damaged compressed files.

How to edit a SIT file?

To make changes to SIT files, you need specialized software that allows both opening and editing the compressed files. Online SIT editors offer fewer capabilities than applications optimized for StuffIt Archive.

Best SIT editors 2026

Based on these criteria, we have prepared a list of available SIT editors.

SIT Editor Software	Developer	Platforms	Overall Rating
StuffIt	Smith Micro	Mac OS, Windows	4.7 out of 5 (39 reviews)
StuffIt Deluxe	Smith Micro	Mac OS, Windows	4.4 out of 5 (40 reviews)

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