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Yesterday, I upgraded my Mac to Mac OS X 10.9 (Mavericks), and since then I couldn’t open the “Terminal,” each time I open a session, the following error is shown:

[Could not create a new process and open a pseudo-tty.]

[Command not found: tmux]

I don’t know what's causing this issue and a fresh restart and killing the relevant processes on activity monitor doesn’t help. Any thoughts?

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The upgrade reset you /bin and /usr/bin etc., if you installed software there, it's now gone. –  Daniel Beck Oct 27 '13 at 14:24
Hi Daniel, so what should be done? Thanx. –  Malloc Oct 27 '13 at 16:56
Don't automatically run tmux when opening the Terminal, instead, run a shell like bash. –  Daniel Beck Oct 27 '13 at 17:56

2 Answers 2

It might be a simple and going into Preferences/Startup/Shells open with and select 'Default login shell'.

It is related to where the Shell you are opening, and you can have multiply shells (but that is another thread'

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I got this error after upgrading from Lion (10.7) to Mavericks. (10.9) This fixed it: Go to Terminal > Preferences > Settings > Shell and uncheck "Run command".

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