Download and install the latest version of Filestar.
Right click on one or more Sitx file(s) on your desktop and select Convert with Filestar.
Type convert to zipx in the search box.
Press Convert.
Or let an AI agent do it: filestarcli -i file.sitx -c "convert to zipx" (how).
Documents - File Explorer─☐✕
This PC › Documents
Home
Desktop
Downloads
Documents
Pictures
Music
.sitxContract.sitx
.xlsxBudget.xlsx
.pdfReport.pdf
.pngLogo.png
Filestar*Help✕
Drop files here to get started
ConvertMergeCompressExtractMoveZip
Let your AI agent convert SITX to ZIPX
Claude Code, Codex, Cursor and other agents can do this on your computer with Filestar. Your files stay on your machine. It works on macOS only.
Install Filestar and add it to your agents:
npm install -g filestar
filestarcli agent install
Then ask your agent:
“Convert the SITX files in my Downloads folder to ZIPX”
Or run it yourself:
filestarcli -i file.sitx -c "convert to zipx"
Runs on your computer, so your files stay on it. Works on macOS. 50 free conversions with the npm install, no account needed.
Can my AI agent convert SITX to ZIPX?
Yes. Install the Filestar CLI with npm install -g filestar and your agent can run filestarcli -i file.sitx -c "convert to zipx" on your computer, so your files stay on it.
StuffIt X Archive (.sitx) is a compressed archive format introduced in 2002 as the successor to the classic StuffIt (.sit) format. It offers stronger compression than the original format and adds encryption, error correction, and self-checking features, while preserving Mac-specific data such as resource forks. It has been widely used on classic Mac OS and macOS for bundling and distributing files.
WinZip, starting with version 12.1, uses the extension .zipx for ZIP files that use compression methods newer than DEFLATE; specifically, methods BZip, LZMA, PPMd, Jpeg and Wavpack. The last 2 are applied to appropriate file types when "Best method" compression is selected.
