Some people face issues with starting up user profile synchronization service. The main thing is that they find it hanging on “Starting”. They resolve this issue by changing the start type for the service to be “Automatic – Delayed Start”.

Please note that changing the services manually is unsupported. The best action is to troubleshoot the issue using the steps in the technet article http://technet.microsoft.com/en-us/library/gg750257.aspx

Note that the article specifically mentions that “The User Profile Synchronization service can take up to ten minutes to start”. In some cases, it even took more than that depending on the environment and the hardware. So, apply the troubleshooting steps, and be patient with the service starting time. You will find that the service will start successfully without changing the start type and going out of support.