When you have more objects than the default 10,000, your active directory searches may not return all the matching objects.
To increase the number of objects searched:
1. Open Active Directory Users and Computers.
2. Right click your domain object and press Properties.
3. Select the Group Policy tab.
4. Select the Default Domain Policy and press Edit.
5. Navigate to User Configuration / Administrative Templates / Desktop / Active Directory.
6. Double-click Maximum size of Active Directory searches.
7. Enable the policy and set the Number of objects returned.
8. Press Apply and OK.
To do this in the registry, modify 00000000 to be the hexadecimal number of objects and then apply the .reg file:
REGEDIT4 \[HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\Directory UI\] "QueryLimit"=dword:00000000You will need to logoff and logon for the change to take effect.