Azure AD Sync Error: Quarantined Attribute Value Must Be Unique

Hi All

We are tyring to implement a password hash sync for our local AD and Azure AD. The first thing we did was to uninstalled the old Azure AD connect from another server which We assume should have removed any old connection or configuration setting and We set up another one on a different server with all the new sync configuration.

Later we created a new OU for sync testing and move a few user over to the test OU. We run into some duplicate issue which we were able to clear beside the one such as in the attachment. We figured out that the account must have been either created first in Azure AD or already synced to an old domain server. The username in that problematic account that synced with the active directory is definitely incorrect from what We see inside the AD server. Now we need to at least know is what we suspect is correct