I use HortonWorks Sandbox for learning/trying out Hadoop features. Now the way Hortonworks Sandbox works is your supposed to download the VM and then ssh into it using ssh root@ -p 2222

for connecting to it or playing with it. Initially i had HDP 2.1 sandbox but when i downloaded HDP 2.2 and tried to connect to it i got WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! error. So basically both HDP 2.1 and HDP 2.2 has a different SSH key but your trying to refer them using same IP and your machine says hey something is wrong your ip is same but SSH key does not match
In order to solve this problem, all i did was to open /Users/test/.ssh/known_hosts file in text editor and then i searched for and i removed the line that started with this ip and saved my known_hosts file
Now when i rerun the ssh root@ -p 2222

command i am able to connect to the HDP 2.2 image ok.