I am new to the simulation add-in for SolidWorks. I have been tasked with optimizing the design of a test fixture we use on a shaker table. Specifically, we want to ensure that all mode shapes of the testing assembly occur above the frequency range we sweep while testing. I have everything modeled and I believe all the proper study constraints in place. The model meshes with no problems. When run the study it starts its calculations as normal but then a few minutes later I receive an error that says, "Stop: 8 - Singular Matrix." I have tried searching for what causes a 'Singular Matrix' error but have not had any luck. Does anyone know what this means or what steps can and should be taken to avoid an error of this type? Below you'll find a screen shot of the error message I receive. Thanks for your help!