Using IDFix to list accounts that require some changes before implementing the synchronization between on-premises and Office365.
The tool is available at Microsoft Download center, you can use the following link http://www.microsoft.com/en-us/download/details.aspx?id=36832 and there is no real installation, after download the file, extract the contents to a folder.
The tool does not require installation, we just need to run the IDFix application.
The tool is simple and to get the initial assessment, click on Query (1) that will trigger a reading of the Active Directory and a list of all mailboxes that contain items to fixed will be displayed (2), a summary of the number of accounts and accounts to be fixed will be listed at the bottom (3). The administrator can take an action (4) to fix the accounts, the goal is to fix as many as you can before starting the synchronization.
Keep in mind that we can filter the objects to be synchronized between on-premises and Azure Active Directory (using OUs, UPNs and etc). Accounts that will never be synchronized don’t have to be “fixed” using this tool.