Ssms ver. 18 GA on windows 10.0.17763. does not work

Just installed ssms ver. 18 GA on windows 10.0.17763. after uninstalling preview.
Start screen appears and disappears immediately … end of working
No relevant event logged
I repaired ssms ver. 18 GA . Behaviour unchanged.
I uninstalled ssms ver. 18 GA and installed Preview 7. Woks fine

so what is your question, what do you need help with?

An observation, hence no question
Additional information
Uninstalled fine working preview 7, then installed GA + Restart. Welcome screen appears than full stop. Hit repair button + Restart. Same full stop. Hit uninstall button and Windows started updating (2019-02 Cumulative Update for .NET Framework 3.5 and 4.7.2 for Windows 10 Version 1809 for x64 (KB4486553) + additional stuff VS C+ etc – see xml file) + Restart. Same full stop. I returned to Preview 7
Computer: Windows 10.0.17763. with SQL 2017 and .net 3.5.30729.4926 and 4.7.03190 461814