We're facing issues while working with Data Preparation in Mac OSX. Even Disabling the App Nap as mentioned here isn't solving the issue. Please look into this at the earliest.
Which version of Data Preparation are you using?
When do you get this error? When trying to add a dataset or a preparation step? Could you please upload your app. log on community?
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Introduction to Talend Open Studio for Data Integration.
Practical steps to developing your data integration strategy.
Create systems and workflow to manage clean data ingestion and data transformation.