I've just installed 12.1 on mac os x 10.8 and am missing all tabs on the right except lights and fur. The rest are not available for adding. Has anyone else seen this?

I think this may be due to the renaming announced at SIGGRAPH

https://www.sidefx.com/index.php?option=com_content&task=view&id=2236&Itemid=66 [sidefx.com]

“Houdini Escape” -> “Houdini”
“Houdini Master” -> “Houdini FX”

If you see “Houdini FX”, you want to launch that instead.