@Jay Kumar Sensharma I tried first two they dont seem to boot up and get stuck on loading screen.I have attached a screenshot.
How much time should i expect it to take when booting for first time?notloading.jpg
Based n your recent screenshot looks like the boot operation is completed successfully (Even though you do not see the welcome message of Sandbox in the mentioned screenshot). So i guess you should be able to access the ambari UI as well as the SSH session to the sandbox without any issue.
So can you please try this:
1. Login to Sandbox using SSH on port 2222 as following:
# ssh firstname.lastname@example.org -p 2222 Enter Password: hadoop
2. You can also try accessing the web terminal: http://localhost:4200
3. Also please try accessing ambari UI to see if it works. http://localhost:8080
Jay's answer looks good - I just wanted to post a note for future reference: When given the option of CentOS versions (or more accurately, kernels), go with the latest one when dealing with the sandbox. Future versions of the sandbox should be removing unused kernels (3.x in this case), but if you are given an option when booting the sandbox - go with the latest.
Although, not making a selection will default to the first (and latest), so all is good either way.