During the pilot testing phase, you may need to modify a profile by changing the Matching Action from ‘Create or Update’ to, for example, ‘Update Only.’ However, you do not notice any difference after selecting a different matching option and saving the DirSync profile.

Matching Action
This is perhaps the most important parameter on Matching Options page. What do you want Directory Sync Pro for Active Directory to do if it finds a match based on your chosen mapping parameters?
1. The default is Create or Update. This means that if Directory Sync Pro for Active Directory does not find a match, it will create a new object in the target. If a match is found, Directory Sync Pro for Active Directory will update the attribute values on the target object using the values from the attributes of the source object.
2. If you choose Create Only, then Directory Sync Pro for Active Directory will create a new object in the target for any unmatched objects. It will not update any attributes for those objects that have been matched. Note: Legacy Password Synchronization does not work with this option!
3. Choose Update Only to update the attributes from source objects to matched target objects. No new objects will be created if a match is not found. A scenario in which you might choose this would be when the users have been pre-created in the target manually, and you just want to keep changes synchronized.
4. And finally, Match Only, No update (option not available for Exchange Intra-Forest Profiles) will make no changes to any objects. This is only chosen when you are using another product other than Migrator Pro for Active Directory for AD synchronization. It will import the values that are needed when Migrator Pro for Active Directory performs the ReACL and Cutover actions. Note: Legacy Password Synchronization does not work with this option!
Please review our product documentation for more details about all the Matching Options.
Resetting a DirSync profile is required before selecting a different Matching Action.
When you reset a profile, all objects that were previously pushed into SQL by the profile will be removed. If this includes devices, you will be prompted to confirm their removal, as this is not typical.
If you reset a profile without removing the objects "pulled" into the target by that profile, consider the relink and "Mark as ready to sync" options on the Matching Options settings page.
IMPORTANT NOTE:
Resetting a profile is uncommon, especially if you are already performing production syncs. It is recommended to perform profile resets during the preparation or testing phase.
Resetting a user profile will also cause the passwords (legacy password sync) to be written to the target. If the user has changed their password in the target, it will be overwritten, which could lead to unintended consequences.