El Capitan on my Mac Mini now but it started when I used
Yosemite. I need both English and Russian keyboard layouts on my Mac. However at some point I started finding Russian layout missing once Mac is launched, so I have to go to the settings and add Russian again every time my Mac starts. Did anybody encounter a keyboard vanishing from the system constantly? What makes it dissapear every time Mac is shut down? Ayn ideas how to fix that?
Go to System Preferences -> Language & Region.
Set English as Preferred language. Unfortunately, your macOS becomes English, but it's the only way that solved this problem on my Sierra 10.12.5.
You could also try to delete