I am having this exact issue. The sound is playing in the background but the visual part of cubase is dead and unresponsive only thing I can do is to close the program in a task manager.
I tried lots of different windows and cubase tweaks but the result was and still is the same and I am really not happy about it 
Ok I fix my problem, it seams Cubase have a problem with some USB devices/drivers.
For me the problem was my keyboard M-Audio Code 61. When another freeze happened I just turned off Code 61 and Cubase came back to life 
I even kept working on the same project for another few hours. Next day I worked for 10 straight hours without a hitch.
So my solution was to connect M-Audio Code 61 through my RME MIDI port (no USBs). I lost some functionalities of the Code 61 like the HUI transport but my system is now rock solid.
So guys try removing your USB devices, you can even try to turn them off when CB freeze, just like I did.
I hope it will be a solution for you too
+1
But very rare and hard to reproduce 
Same here. For months, possibly years. No idea what causes it. Sometimes it takes my whole system UI down and I have to SSH in and reboot it remotely. My guess is it’s audio drivers or plugin related, or possibly an issue with the 3rd-party system SSD drive I’m using, but nothing in the system log or crash logs gives any useful information.
Hi there, I have the same problem.
It was gone for a while, but it is back.
I have not the very newest system, still on i7 -3930k with Nuendo.
Asus Board P9 X79-E WS. I use a RME UCX with Firewire connection / Latest hw drivers, latest software drivers, latest firmware.
Basically tried almost EVERYTHING in the last months to have a stable system, except re-install the whole system completely, since I have a continuous amount of work to do and no time for a complete fresh install at the moment.
During the last year, I changed the harddrives to faster ones, bought another low profile graphic card to avoid the Nvidia bug on Win10,
did weeks of research to optimize Kontakt and deinstalled basically all background services that I could possible think of being a problem.
My system worked for a while with the Free Version of Bit Defender, but also got rid of it now, since suddenly Nuendo started to have the same issue again.
I still have the feeling that this issues appear more when I work with older, or “slightly bad” programmed Kontakt Libraries. Some people like Evil Dragon told me again and again that it can’t be the case, but I work for days sometimes with the Kontakt Libraries I know to trust and have no crash at all. If I get back to some that I don’t know or older ones, the crash / freeze issues re-appear.
Still, I can work with several instances open with Novo, Forzo, Saga and some more pretty intense and resource hungry scripting without any problem. (if I watch the maximum voice settings etc. to avoid CPU spikes) …
I am getting really really sick of this and would be curious if people have the same problems on Presonus Studio One?
On Ableton, I could not test the whole procedure…