If an error occurs during an attempt to synchronize a password, an error is logged in your event viewer. The password hash synchronization feature automatically retries failed synchronization attempts. When you change an on-premises password, the updated password is synchronized, most often in a matter of minutes. However, if there are multiple connectors, it is possible to disable password hash sync for some connectors but not others using the Set-ADSyncAADPasswordSyncConfiguration cmdlet. You cannot explicitly define a subset of user passwords that you want to synchronize. Staged Rollout allows you to selectively test groups of users with cloud authentication capabilities like Azure AD Multi-Factor Authentication (MFA), Conditional Access, Identity Protection for leaked credentials, Identity Governance, and others, before cutting over your domains. The first time you enable the password hash synchronization feature, it performs an initial synchronization of the passwords of all in-scope users. When you synchronize a password, it overwrites the existing cloud password. You cannot modify the frequency of this process. The password hash synchronization process runs every 2 minutes. However, passwords are synchronized more frequently than the standard directory synchronization window for other attributes. The actual data flow of the password hash synchronization process is similar to the synchronization of user data. Passwords are synchronized on a per-user basis and in chronological order. Extra security processing is applied to the password hash before it is synchronized to the Azure Active Directory authentication service. To synchronize your password, Azure AD Connect sync extracts your password hash from the on-premises Active Directory instance. There is no method to revert the result of a one-way function to the plain text version of a password.

A hash value is a result of a one-way mathematical function (the hashing algorithm). The Active Directory domain service stores passwords in the form of a hash value representation, of the actual user password.

This article provides information that you need to synchronize your user passwords from an on-premises Active Directory instance to a cloud-based Azure Active Directory (Azure AD) instance.

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