I have learnt that latest community edition shows window with info that it has not been opened or installed properly last time - even If You are installing for 1st time.
later You can not see core activities…
I have found solution for BUG:
copy the file with activities as aforementioned in other tpics (keyword:core activities for search) to destination path (C is whatever your windows install disk_)
c:\Users\xx\AppData\Local\UiPath\app-2016.2.6379.27755\Packages
, but…
open packages.config (XML) file that is present in the same folder and update file name in xml line which adressess package to 2016.2.6379.27755 or whatever you have…
because there is bad link to older version in this config file!!!