Parallelisation resulting in

While trying to simulate the Cantilever Modal 3D, I tried two methods. Once without parallelisation and again with parallelisation. Without Parallelisation, the model simulated and gave results within 10 seconds. But while simulating with Parallelisation, the model went on simulating for 10+ minutes. It never stopped simulating and I cancelled the job at last. I tried this test on sample project 1 as well, but there parallelisation worked perfectly.