Dear Hans van der Meer,
Thank you for your solution. It is similar to the one of the engines, which is for ConTeXt(beta, stand alone) and works fine.
Thank you again.
On OSX there are directories used by TeXShop one of which is ~/Library/Engines. The text files there contain scripts that callup a tex run. In my case I have a text file called BetaCur.engine to be found in the run popup button of TeXShop. In it I have: #!/bin/bash source ~/.bashrc mtxrun --script context "$1"
In the .bashrc file in my home directory the directory where the ConTeXt files reside is given amongst other defines: CONTEXTROOT=$HOME/Applications/TeX-programs/directory-of-my-contextbeta-files/tex export CONTEXTROOT PATH=$PATH:$CONTEXTROOT/texmf-osx-64/bin