Hi Thor,
thank you very much for your fast reply.
In general you are absolutely right with what you said and a test workflow I just created runs perfectly fine creating the .knimeLock file during execution and deleting it afterwards.
BUT unfortunately the original workspace resulting always in the above error message does NOT contain a .knimeLock file.
Nevertheless it throws this unfortunate error message. Is there anything else that triggers this message and why does the same workflow finishes perfectly in the GUI but not in batch mode on the command line? (Of course GUI is closed at this time)
Thanks a lot for your help