Dear Nektar group: I installed a serial version of Nektar++_4.3.3 . When I ran ctest, the 13th test showed the following messages, and then it looked like no response or to be paused. Start 13: StdRegions_StdProject2D_Quad_Orth_P6_Q7 13: Test command: /home/sk1/nektar/build/tests/Tester "/home/sk1/nektar/library/Demos/StdRegions/Tests/StdProject2D_Quad_Orth_P6_Q7.tst" 13: Test timeout computed to be: 9.99988e+06 When I reduced the order by replacing "4 1 1 6 6 7 7" with "4 1 1 4 4 7 7" in the file "StdProject2D_Quad_Orth_P6_Q7.tst", the 13th test passed. After trying many times ,I found order1>4 would lead to this trouble. Moreover ,a tutorial case "basics-advection-diffusion" encountered similar problem. In the file "ADR_conditions.xml", NUMMODES>4 for COMPOSITE="C[2]" would lead to problems. I got the messages, and it looked like no response. ADRSolver ADR_mesh_aligned.xml ADR_conditions.xml ======================================================================= EquationType: UnsteadyAdvection Session Name: ADR_mesh_aligned Spatial Dim.: 2 Max SEM Exp. Order: 5 Expansion Dim.: 2 Riemann Solver: Upwind Advection Type: Projection Type: Discontinuous Galerkin Advection: explicit AdvectionType: WeakDG Diffusion: explicit Time Step: 0.001 No. of Steps: 1000 Checkpoints (steps): 100 Integration Type: ClassicalRungeKutta4 ======================================================================= Initial Conditions: I noticed that quadrilateral mesh was used in above two problems . The 13th test used quadrilateral mesh, while the "basics-advection-diffusion" case used multi-region mesh (region 2 was quadrilateral, region 1 and 3 was triangle ), and the NUMMODES>4 for quadrilateral region would lead to problems. Why? How to fix it? Thanks. SONG Ke