Hi,
Since last build, 2018.23760, the clear output parameter on the GLSL TOPs is set to on by default. It seems that it’s causing some previous projects involving GLSL not to work properly anymore. I would suggest to turn it off by default.
You can see that the Compute Flocking from Noah is not working in the last build:
viewtopic.php?f=22&t=11909
Going to ComputeFlock/ComputeParticleSystem/Particles and changing the parameter solves the problem.
Thank you for your time,
Michel