This policy setting allows user-based policy processing, roaming user profiles, and user object logon scripts for interactive logons across forests.

This policy setting affects all user accounts that interactively log on to a computer in a different forest when a trust across forests or a two-way forest trust exists.

If you do not configure this policy setting:
- No user-based policy settings are applied from the user's forest.
- Users do not receive their roaming profiles; they receive a local profile on the computer from the local forest. A warning message appears to the user, and an event log message (1529) is posted.
- Loopback Group Policy processing is applied, using the Group Policy Objects (GPOs) that are scoped to the computer.
- An event log message (1109) is posted, stating that loopback was invoked in Replace mode.

If you enable this policy setting, the behavior is exactly the same as in Windows 2000: user policy is applied, and a roaming user profile is allowed from the trusted forest.

If you disable this policy setting, the behavior is the same as if it is not configured.