Any time I try to open Houdini it is a total gamble if it will work or not. Today I wanted to do some work but instead I have restarted the system, cleaned out shit etc for 1.5 hours without solving it. Horrible experience.
Has anyone a solution? Surely the licensing system (from last millennia, from the lower circles of hell) must change soon?

Sounds annoying, I have not seen this behavior myself. Have you contacted support? Are you using your machine as a local license server or sidefx.com?

Same here, license hasn't been an issue for me. What version and OS are you running on? There was an old license issue way back when, but we're talking about three years ago. It got fixed a while back.

Seriously? I just use H on Mac laptops and there is always problems. Been like that for many years. On Stationary PC (win or linux) I never have any issues. I usually start by trying to solve it myself for a few hours. It has something to do with networks it seems. Some networks work better than others. Very odd. Then I contact support that usually is very nice and tries to help. Sometimes I will have to let them recall my licenses and have me reinstall Houdini. You get the point, not the thing you want to happen when you need to do work.
After I get it to work this time I will try to use their server instead (That of course doesn't support using safari just to rub in that Mac users are second class customers )

EDIT/resolved:
To sidefx credit, they have a very nice support team that tries to help you swiftly. In this case they had to report licenses as lost and then I used their online server for licenses instead. Was some bugs (you can't use the button in the admin gui to set the online server, instead you have to fill in "https://www.sidefx.com/license/sesinetd [www.sidefx.com]" manually.)