If you turn off this feature, Windows waits for the network to be fully initialized before users are logged on. This results in the synchronous application of policies when the computer starts and when the user logs on. This application of policies resembles a background refresh process and can reduce the time that is required for the Logon dialog box to display and the time that is required for the shell to be available to the user. An administrator can change the default by using the Group Policy MMC snap-in.
Fast Logon Optimization is always off during logon when a user first logs on to a computer.
You should be aware that, under the previous conditions, computer startup can still be asynchronous. However, because logon is synchronous under these conditions, logon does not exhibit optimization.
When your folder redirection policy is not completely applied at first logon, you can find the following warning in the event log:
Folder redirection and software installation policiesBe aware that when logon optimization is turned on, a user may have to log on to a computer two times before folder redirection policies and software installation policies are applied. This is because applying these kinds of policies requires the synchronous policy application. During a policy refresh (which is asynchronous), the system sets a flag that indicates that applying folder redirection or a software installation policy is required. The flag forces synchronous application of the policy at the user's next logon.
Note This also applies to systems that are running Windows 7 or Windows 8. However, in those systems, the event ID changes to 510:
For more information about the effect of Fast Logon Optimization and Fast Startup on Group Policy settings, go to the following Microsoft website: