I've read on here about running two Safari instances side by side, but for running two versions of an app side by side, is this possible on OS X other than using a VM? In my case, it's Big Sur, latest version on a 2019 MacBook Pro.

A VM is overkill in this instance, as this is only for something like BBEdit, a HTML editor, or those sort of programs.

How would you have two apps, but not sharing preferences, on the same user account, or is this not possible? I've already got a second admin account but this is more for my day-to-day one.

It's for BBEdit.

I'd welcome any advice as I've done some Google-ing but aren't sure.


Essentially, this can only be done if the apps have different signatures [I think they're now UTIs, used to be Creator Codes].

Persuading an app to run twice can be as simple as duplicating it in the Finder, but persuading it to use a different set of prefs means being able to 'fool' the OS into thinking it is, indeed, a separate app, with its own signature & prefs naming convention.
This can only typically be done at compile, which of course requires you have the source code - these days hindered further by having to have valid developer certificates.

In the days of BBEdit having a 'junior' app, TextWrangler, this would have been easy.

  • 1
    Thank you for this, much appreciated
    – avenas8808
    Aug 26 '21 at 13:29

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