So, I installed Houdini 13.0.476 the other day, and I got this “License Error: Unable to connect to hserver for license acquisition” when I tried to start HoudiniFX. I thought that was strange, because I had been running 13.0.401 moments before.
According to the licensing FAQ, that error means that the hserver service isn’t running. And, in fact, neither hserver nor sesinetd were running: they were both Disabled and marked for deletion, so I couldn’t start them from the Services console. After closing down Process Explorer, Task Manager, and the Services console, I was able to delete the services from the command line with sc delete.
At this point, I could have tried creating the services with sc create, but I was curious to see if the Houdini installer would do it for me. So I uninstalled and reinstalled. The installer asked me if I wanted to replace the newer version of sesinetd that was already on my system (huh???), and I clicked Yes. After the install finished, I had a running sesinetd service but no hserver, so I had to create it myself:
sc create HoudiniServer binPath= C:\windows\system32\hserver.exe
After that, I was able to start HoudiniFX and acquire a license.