Yeah why? This goes for both Mac and PC.Sometimes it fails (mainly on PC). Very very annoying.
This is for the Apperentice version. Is it the same for the real versions? Would be terrible to not be able to realy on software starting when needed.

I had same issue, this is what SideFX support said:

The Houdini-Apprentice license is a 30-day license, and your current Houdini-Apprentice license has expired.
(yes, you will have to do this every 30 days - I asked)

To reinstall a new Houdini Apprentice license please do this:

1) Delete your licenses and licenses.local file under C:Windows/keys

2) Do a full install of Houdini 17.0.429
You will find this build on our web site, under Get -> Download -> Daily Builds
Install this as a commercial license, as this will reset your license server to 17.0.429

3) Relaunch Houdini, and follow the prompts to install a new license

If trying to reinstall Houdini-Apprentice give you errors, then this process usually resets your Apprentice install process, and allows you to reinstall the license.

Installing Apprentice as a commercial license reinstalls the license server version with the license tools. This can often help with install errors.

Thanks for the reply, then I might be able to save the PC tomorrow. So this thing will not happen on commercial licenses I take it? Surprised by the general buggyness of the software. Hands down the software that have resulted in most crahes for me in many years. Compensated by a lot of awesomeness in functionality though

filipw
Hands down the software that have resulted in most crahes for me in many years

please file bug reports about any crashes you have and be sure to include your machine specs