It is hard to say what could have happened. Were there any patches or changes made to your operating system (and what OS is it, Windows or Linux)? What is the full version (2018.1.0 or 2018.1.2. or ???)? Any additional details you can provide may help.
Its windows 10 pro and 2018.1.2 TS version.
we didn't make any changes in our host.
2-3 weeks ago we upgrade server from 10.3 to 2018.1.2
We have 24gb free space in 'c', maybe it is potential problem?