All Solutions

Warning: New constraint force nodes detected

Solution Number: 1056 Versions: All versions

I get this error message: Warning: New constraint force nodes detected. What does it mean? As is indicated in the message, this is a warning message and not an error message, meaning that your model may be just fine. ...


Error: "Out of memory"

Solution Number: 1030 Versions: All versions

I get an error message, that contains the words Out of memory, for example: Out of memory during LU factorization. or Out of memory during assembly # Background Before resolving this issue, you should go through ...


Updating the COMSOL License Manager

Solution Number: 1022 Versions: All versions

When starting COMSOL Multiphysics, I receive this error message: Could not obtain license for COMSOL Multiphysics GUI. License error: -25 License server system does not support this version of this feature or ...


License borrowing

Solution Number: 1016 Versions: All versions

How do I borrow license keys on a floating network license or a class-kit? License borrowing means that you can use COMSOL (for a limited time) with a Floating Network License (FNL) or a Class Kit license (CKL) without ...


Running COMSOL® in parallel on clusters

Solution Number: 1001 Versions: All versions

This solution describes how you enable distributed parallelization (cluster jobs) in COMSOL Multiphysics®. COMSOL supports two mutual modes of parallel operation: shared-memory parallel operations and distributed ...


Error: Internal Error in Geometry Decomposition

Solution Number: 983 Versions: All versions

Why do I get the error message “Internal error in geometry decomposition”? This error means that COMSOL Multiphysics failed to resolve the geometry relations. If your geometry consists of several objects, the objects ...


My flux calculation seems wrong

Solution Number: 973 Versions: All versions

I am solving a diffusion-like problem in COMSOL Multiphysics and discovered that boundaries that are defined with insulation/symmetry conditions have an integrated value of the normal component of the flux that is far ...


Error: Failed to find a solution. Returned solution is not converged

Solution Number: 964 Versions: All versions

I get this message: Failed to find a solution. The relative residual (0.28) is greater than the relative tolerance. Returned solution is not converged. Messages similar to this are returned for nonlinear problems ...


Error: Singular Matrix

Solution Number: 953 Versions: All versions

What does the error message "Singular Matrix" mean? The problem is that the stiffness matrix of the linear system is singular and the linear solver cannot invert it. Examples of practical modeling situations where this ...


Avoiding negative concentrations

Solution Number: 952 Applies to: COMSOL Multiphysics, CFD Module, Chemical Reaction Engineering Module, Electrodeposition Module, Microfluidics Module, Subsurface Flow Module, Mixer Module, Corrosion Module, Electrochemistry Module Versions: All versions

Why do I get negative values of the concentration in my diffusion, convection and reaction model? Why do I see values that go below, or above, their lowest, or highest, possible values based upon the boundary ...