I resolved my issue with the visual editor using @andreD300 steps plus a few more that solved my problem.
1. In WP admin panel Tools > Upgrade > Reinstall
2. In Firefox Tools > Clear Private Data
3. In WP admin panel Settings > WP super cache > Delete cache
4. Log out
5. log back in
Initially when I logged back in it looked like the problem was not solved. When I switched from html to visual mode the editor was back.I hope this helps.