StuffIt library file
File type: Various data file
The .sitl file extension identifies a StuffIt library file. It contains library data used by the StuffIt file archiver.
File type category:
Various data file
Date updated: September 30, 2026
SITL files are proprietary data files associated with StuffIt, the file archiving software historically available for Macintosh and Microsoft Windows. They support the program's library functions rather than serving as ordinary documents.
A SITL file is normally used together with the StuffIt installation and its other data files.
Open a SITL file with the compatible StuffIt installation on Microsoft Windows. These files are generally support data for the program, so opening the associated StuffIt application may be more appropriate than opening the file directly. A SITL file may not be useful without the related installation and its other data.
SITL files do not normally have a meaningful standalone conversion. If the compatible StuffIt software can read data from the library, use its available export or archive commands to save that data in a currently supported format. Generic archive converters should not be expected to process a SITL file.
Software applications that handle other tasks involving sitl files:
Microsoft Windows
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