Resharper disappeared from Visual Studio 2013 (running). I restarted Visual Studio, then Windows 10, but still no luck.
Then I observed Resharper was uninstalled completely in Windows 10 programs and features. (dotPeek was not uninstalled)
The only act which I think could affect Resharper was an upgrade of Visual Studio 2017 from 15.2 to 15.4, but I did not get any warnings, nor did I confirm uninstall of any extensions.
No other users has access to my PC. I know the product very well: Every day user since 2006!