Due to recent bot attacks we have changed the sign-up process. If you want to participate in our forum please send a message via our contact form. › Forums › OpenLB › General Topics › I cannot run cylinder2d example?! › Re: I cannot run cylinder2d example?! October 24, 2016 at 8:20 pm #2469 mathiasKeymaster Dear Klaus, just run “make” instead of “make j4” and it will work. Best Mathias