Today I installed R# 2018.3 and I have about 1880 unit + integration tests in my solution. In previous versions of R# when I open the Unit Test Explorer window and right-mouse click my tests I could choose Run Unit Tests and it would automatically start a new Unit Test Tession. As of R# 2018.3 when I try that nothing happens and in the Unit Test Sessions window I see "no open unit test sessions".
When I right-mouse click the top entry of my tests and choose "Create New Session" (Ctrl + U + N) it does create a new session but nothing happens, the tests are not run and the tests count is incorrect.
Even when I click the 'play' button to run all the tests nothing happens. Furthermore I see this in the right corner of my status bar:
I tried a repair installation of R# 2018.3 twice, but I still had this problem.The only solution was to fallback to R# 2018.2.3 and it immediately started to work again as before.
What could explain this behavior?