Мэттью
Hi,
The behaviour of Houdini closing without informing the user was partially fixed within the past week or so (next production build) and was fully fixed in the next release.
Some other useful tips for determining an issue specific to licensing:
Generate a license diagnostic from hkey/sesictrl.
As you can see in the screenshot above, there are no problems with the license.
The problem apparently turned out to be in the video card, but for this I had to guess, although I expected to see this message from the houdini.