If you uninstall Windows Azure Active Directory Sync (DirSync) from a server then later decide to reinstall it, you will get one of several possible errors. You will not be allowed to to reinstall DirSync unless you delete the SQL server database and possibly delete system accounts that are created on install. I had all sorts of fun challenges when moving DirSync to a different server then back again later when other priorities dictated that was the best move. Early on in the uninstall process I was at a loss to find any good articles on the internet after trying several comprehensive search phrases and I was wasting too much time clicking around.
When trying to reinstall DirSync the most common error message I got:
The install was unable to setup a required component. Check the event logs for more information. Please try the installation again, and if this error persists, contact Technical Support. Unable to uninstall the Windows Azure Active Directory Sync tool. Use the Control Panel to remove the Directory Sync tool.
There was one time during testing when DirSync failed to uninstall completely which was really fun. I had to take a deep dive into the registry at that point. Then I finally found a great article about a very similar experience and actually used the article more than once over the span of several months. Thank you Mr. Turley!
I used different techniques for the different uninstalls but the two easiest and most effective were to delete the system accounts that are created when installing DirSync and delete the SQL database that is also created during the install process. Boom, done.
If you are interested in installing the latest version of DirSync where these problems are no longer an issue read this: