SIT! File Extension
StuffIt Expander Archive Format
- File Type sit!
- Developer Smith Micro Software, Inc.
- Popularity
- Application StuffIt Deluxe
- Category Compressed Files
What is a SIT! file?
StuffIt Expander Archive Format, identified by the SIT! extension, is a Compressed Files type and includes 820 files.
The StuffIt Expander Archive Format (SIT!), created by Smith Micro, is one of file format they developed, and they also built 7 programs to support them.
SIT! file support extends to various operating systems, including Windows and Mac OS. When working with SIT! files, you can rely on 3 programs, including StuffIt Deluxe, StuffIt Expander and StuffIt.
Programs that support SIT! files
How to open a SIT! file?
If you can’t open a SIT! file, it is usually because the necessary software is missing. To resolve the issue, select the right program from the list for your operating system. Then go to the official website of the developer, download the software, and install it.
When it comes to opening and working with SIT! files, StuffIt Deluxe, StuffIt Expander and StuffIt are the top choices for users. To install the updated version of StuffIt Deluxe, simply go to the Smith Micro site and download the installer compatible with all major platforms.
Once the process is complete, StuffIt Deluxe should take over as the default application for SIT! files.
Set StuffIt Deluxe as the default SIT! program
Changing Default Programs in Windows
- Right-click on your SIT! file, then choose the "Open with" option and select "Choose another application" from the available options;
- In the pop-up window, select the StuffIt Deluxe application;
- Check the "Always use this application" checkbox, and then click "OK" to apply the selected application as the default for opening SIT! files.
Change Default Program on Mac
- Right click or Control + left click on the desired SIT! file;
- Select "Open in application" and click "Other";
- At the bottom of the window, you will find the "Enable" menu. Default, will be set to "Recommended Programs";
- Choose "All Programs" in this menu and search for StuffIt Deluxe. Check the box next to "Always open in app" to make it the default program.
How to edit a SIT! file?
To edit SIT! files, it is essential to install software that supports not only viewing but also editing the compressed files. Online SIT! editors provide limited functionality compared to full-featured software for StuffIt Expander Archive Format.
List of Top SIT! editors 2026
Based on the criteria above, here is a selection of SIT! editors you can use.
| 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) |
Solve problems with SIT! files
Rest assured, any issues with SIT! files can typically be addressed with simple software adjustments. See the tips below for help.
Why does StuffIt Deluxe stop responding or crash intermittently?
StuffIt Deluxe crashes can be caused by outdated software. Keep your Smith Micro products up to date by installing the latest updates.
Restarting your computer will solve many common problems, which is why it’s the first thing you should do before changing any settings related to the software.
What are the best practices for repairing a SIT! file that has gone bad?
Use a data recovery program to open the damaged SIT! file and from the menu choose "Repair" function to start the repair process. Allow the recovery process to complete, which will automatically repair the damaged compressed files.
What are the warning signs that my SIT! file may be corrupted?
Common indications of damaged SIT! compressed files are:
- Error messages appear during the course of working with the file;
- Editing the archive in StuffIt Deluxe results in slow or unresponsive behavior;
- Opening the file results in an error or a failed attempt;
- Unexpected expansion of the total size of the SIT! file;
- Opening the file in StuffIt Deluxe or other programs causes them to hang or crash;