Please follow and use the following steps, it will centainly help your concern. Cross-org Mailbox Moves Cross Org migrations are the ones where a mailbox needs to be moved from one Exchange Organization to another. Since there can only be one Exchange Organization per Forest, that means moving the mailbox between two different Forests. Exchange Migration Wizard was used to perform this task in Exchange 2003. Exchange 2007 has incorporated Cross Org migrations into the server code base, so now Administrators can perform these moves by using the same task used for Intra Org migrations: Move-mailbox. The following versions are supported for this kind of move: Source Server: Exchange 2000 SP3 (or later) Exchange 2003 SP1 (or later) Exchange 2007 Target Server: Exchange 2003 SP1 (or later) Exchange 2007 Exchange Permission requirements: Logon account for the user who is running Move-Mailbox needs to be a granted the "Exchange Recipient Administrators" role for Source and Target Forests and "Exchange Servers" role for both source and target Server. Permissions for legacy Exchange Servers remain the same as they were for Exchange 2003 Migration Wizard. Process Overview Move-Mailbox in a Cross Org scenario can be divided in the following steps: Open Server Connections Connect to the source and target server - checks if credential and server version is valid Gather Source Information Read source User Mailbox attributes Check if source mailbox is a system mailbox (Fail if it is) Check if source user does not have a mailbox (Fail if it does not) Gather Target information Check mailbox size limit against target database limits Check if we can match the source NT account in the target Forest (account match based on SMTP address, source objectSID and target sidHistory, and legacyExchangeDN). If match is found, this account will be email enabled. Check if target mailbox exists (used to determine if merge is needed) Check if source mailbox is a resource mailbox (If it is the target user must be disabled) Update Directory Information before Move Lock access to source mailbox Create the target mailbox Lock target mailbox Move Mailbox Content Move the mailbox content Update Directory Information after Move Update mailbox location attributes on source and target user accounts Unlock target mailbox Post-Migration Cleanup: Remove Source mailbox / Remove AD User if cleanup parameter was used Unlock Source mailbox if no cleanup was specified

Please follow and use the following steps, it will centainly help your concern. Cross-org Mailbox Moves Cross Org migrations are the ones where a mailbox needs to be moved from one Exchange Organization to another. Since there can only be one Exchange Organization per Forest, that means moving the mailbox between two different Forests. Exchange Migration Wizard was used to perform this task in Exchange 2003. Exchange 2007 has incorporated Cross Org migrations into the server code base, so now Administrators can perform these moves by using the same task used for Intra Org migrations: Move-mailbox. The following versions are supported for this kind of move: Source Server: Exchange 2000 SP3 (or later) Exchange 2003 SP1 (or later) Exchange 2007 Target Server: Exchange 2003 SP1 (or later) Exchange 2007 Exchange Permission requirements: Logon account for the user who is running Move-Mailbox needs to be a granted the "Exchange Recipient Administrators" role for Source and Target Forests and "Exchange Servers" role for both source and target Server. Permissions for legacy Exchange Servers remain the same as they were for Exchange 2003 Migration Wizard. Process Overview Move-Mailbox in a Cross Org scenario can be divided in the following steps: Open Server Connections Connect to the source and target server - checks if credential and server version is valid Gather Source Information Read source User Mailbox attributes Check if source mailbox is a system mailbox (Fail if it is) Check if source user does not have a mailbox (Fail if it does not) Gather Target information Check mailbox size limit against target database limits Check if we can match the source NT account in the target Forest (account match based on SMTP address, source objectSID and target sidHistory, and legacyExchangeDN). If match is found, this account will be email enabled. Check if target mailbox exists (used to determine if merge is needed) Check if source mailbox is a resource mailbox (If it is the target user must be disabled) Update Directory Information before Move Lock access to source mailbox Create the target mailbox Lock target mailbox Move Mailbox Content Move the mailbox content Update Directory Information after Move Update mailbox location attributes on source and target user accounts Unlock target mailbox Post-Migration Cleanup: Remove Source mailbox / Remove AD User if cleanup parameter was used Unlock Source mailbox if no cleanup was specified