I am new to Mac and am trying to install a Hex Editor. Google sent me to "Hex Fiend", but, when I try opening it, I get "'Hex Fiend.app' can't be opened because it is from an unidentified developer."

How can I tell Mac to install and trust Hex Fiend? Ideally, I'd like to keep the setting of "identified developers only" and just make an exception this time. Or, is there another Hex Editor I can use? I'd just like to be able to edit hex!

UPDATE: I tried the answers below, but they don't work, because I'm trying to do Open With from Finder (that is, click on the file, choose open with Hex Fiend). Is there a way to do that? If not, how can I shut off this setting?

  • 3
    Open Hex Fiend first, then try open with... Once you open it once it will stop asking you.
    – dwightk
    Apr 17, 2015 at 18:01

3 Answers 3


Very simply…

Right click it & select Open.

That will bypass Gatekeeper for that one app

See: OS X: About Gatekeeper


I always do it like this: right click, then keep pressed Alt down, an click open.


To change the preferences; click the apple at top left of screen. Click system preferences. Click security and privacy. Press the lock at the bottom left of the window to unlock changes. Select "Anywhere" under "Allow apps downloaded from". After you have opened the app for the first time you can change these preferences back and will still be able to use the app.

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