MigrateWindowsProfiles - sharedmemory.net

Migrating a Windows profile to a new domain

Backup the user profile
As local admin, join the PC to the new domain
Logon to the domain as the user
Reboot and logon as domain admin
Make sure hidden files are shown
Copy the contents of the old profile over the top of the newly created profile, select yes to overwrite
Right-click on the new profile and select Properties > Security
Remove the old domain user and add the new user with Full Control
Run regedit
Highlight HKEY_USERS, and go to file > load hive
Find the users NTUSER.DAT (ensure you have hidden files visible), and load this file. Type anything for the name as this is just the subkey that the user’s registry hive will appear under.
Right-click on that subkey and choose Permissions. You will see the old SID which can no longer be resolved to a user account name because it belongs to the old domain, to which the machine is no longer joined. Delete that SID, and add the user again from the new domain with full permissions.
Unload the hive from the file menu (otherwise the file will be locked/in use and you won’t be able to use it).
Reboot