ReStuff is brought to you by joshua stein @jcs and is now powered by the excellent Infinite Mac software by Mihai Parparita. @mihai ReStuff will automatically convert uploaded StuffIt 5+ archives into StuffIt 3 format and present them to you for download. Just drag-and-drop archives (or click Upload File(s) below the screen) and click the button in the Mac window to start the conversion. Once completed, your browser will prompt you to save the resulting files. StuffIt is the de-facto standard for file archiving and compression on Mac OS before OS X. Most old Macintosh software is preserved in StuffIt format, but a format change in StuffIt 5 makes archives created in this version unreadable in older versions of StuffIt. Since StuffIt 3.5 is the last version that works on System 6, many archives cannot be opened on compact Macs running System 6. Click to expand...

Note that you'll need WebAssembly for this because it's actually running on a Mac emulator. Any chance of getting it to run on a _real_ Mac?

Not sure what "WebAssembly" is but all I did was click Eric's link , then I used Stuffit Deluxe 16 on my modern Mac (runs even on Sonoma!) to make a "Legacy" *.sit file of something (which makes Stuffit 5.x archives), then I dragged that SIT file onto the emulator, then I clicked the button. I saw it do its magic, and I was able to download the Stuffit 3.x SIT file without issue. I then used Stuffit Deluxe 16 on my modern Mac to easily unStuff it. It all worked very seamlessly!

I think this is neat because you can now make SIT files that will open using older Stuffit Expander versions that only run under System 6. GREAT!

WebAssembly (a feature for web browsers that allows emulators and the like to run) has been in around for a while now, this is for people who have a more modern computer and want to restuff it.

To do this on a real vintage mac you'd just install stuffit 5 and 3. If you don't have a mac that supports stuffit 5 and you dont have a modernish web browser, you'll have to ask a friend.