tl;dr I can't get a particle system I downloaded to work, despite doing everything by the book. I downloaded a custom particle system (it was made prior to the steampipe update, if that matters somehow). It came without a readme file, it had only the .pcf file, so I followed some short explanation about how to set particles up by wiseguy149, from a previous post on this subject: What I did is place the particle file in .../tf/custom/custom stuff/particles. Then I placed a info_particle_system in my map, and set the Particle System Name to the .pcf name (w/o a directory, as it should be the proper location) After that, I made a .txt file, as instructed, called in the exact same name of my map, with the added _particles suffix. I placed it in .../tf/maps- where my map is stored. I loaded the map, and using ent_fire, attempted to start the particle system via the start input. It didn't work, and the consule said: Attempting to create unknown particle system <the particle system's name>. Just to make sure, I used the particle editor to ensure the particle itself is all good, and it works there just fine, as far as I can tell. Any ideas what went wrong?