Let me first describe all issues I had at once :)
unknown error .../Roaming/Microsoft/Visual Studio/ActivityLog.xml
Could not locate appropriate CLR version. Try rebooting, reinstalling.
Failure calling VsHookCLRLoading.
Failed to initialize the Common Language Runtime (CLR) v4.0.30319 with HRESULT 0x80004005. You may fix the problem and try again later.
(unfortunately I didn't capture exact error but Terminal just started and showed error like 0x........)
What was that? In my case it was just windows update installed :)
after some googling I have found solution from microsoft and in my case this one line resolved all issues:
dism /online /enable-feature /featurename:netfx3 /all
if you have WCF then you may need these two as well:
dism /online /enable-feature /featurename:WCF-HTTP-Activation
dism /online /enable-feature /featurename:WCF-NonHTTP-Activation
Thank you and good luck :)