Workstation suddenly was FROZEN. To reload I Power Switch off Virtual machine.
After new load Virtual Machine Critical error was obtained one time and next time such information was missing.
Hidden Service stopped to work (cannot connect to website). In menu disappeared Soft “Tor reload”.
How I can renew system functionality ?
Additionally I found
Directory ‘/usr/local/etc/torrc.d’ does not exist
ls: cannot access ‘/var/lib/tor/hidden_service/’: No such file or directory
Which Whonix version did you initially download?
Using which Whonix repository? Developers, testers, stable-proposed-updates or stable repository?
Did you create a Tor onion service?
If not: then that folder /var/lib/tor/hidden_service is expected to not be existing.
Please post error messages. Otherwise I cannot make head or tail of it.
Whonix 15.0.0.6.6 - this is version.
Which repository I do not know I newbie… 
Yes, I created Tor onion service which worked perfect.
Error massage was such that I must get log and ask with it professional help with forum. Something like this.
Frozen was Workstation.
Hidden Service stay with Gateway.
That is why all with gateway is OK and described above files are present.
I with error tried to find them with Workstation… 
This sounds more like a VirtualBox and/or hardware issue rather than Whonix issue. I don’t think I can help with it.
Maybe the VirtualBox guru mediation thing. However, that is too general. Specific error messages are required.
See also:
And:
https://www.whonix.org/wiki/Free_Support_Principle
how I can reinstall only workstation to keep all good worked installed software and modules ?
Your version of VirtualBox files install simultaneously Workstation and Gateway.