If you’re like me, and prefer to use millimetre measurement units (MMGS) in your favourite CAD program you’re going to have a very bad time in COMSOL. By default, COMSOL will assume that a imported DXF file uses meters (MGS). The result will be that your simulation runs fine, but you may find that “nothing happens” or the “plot is frozen” due to the three-orders of magnitude error affecting the calculations.
I’m too embarrassed to say how many hours this took me to solve this one.
Conclusion: In life, it’s the simple problems that wear you down.