This happens every few versions...
anyone with similar problems?

The software checks that the underlying PC has not 'changed' significantly.
(This check can be random, but always happens when you update the software.)

The chnange can be a hardware change, such as a disc added, or a CPU changed, etc.
It can also be a large OS change, such as changing the OS from Windows 8 to 10, or even a large upgrade to the OS as with the recent 'Anniversary' update for Windows 10 (that upgrade was such a huge change the OS registration 'changed' within Windows itself).

See: http://www.lightillusion.com/upgrades_licenses.html

The above are the only times the license will 'lock out'.
All that is then needed is an e-mail to us, with the license code included, so it can be reset.

Steve

Ok - just so anyone reading this at a later date knows, Tomer changed his GPU, so the license lockout is expected, as the Support pages of the website explain.

http://www.lightillusion.com/upgrades_licenses.html

Steve