How do I modify the number of Active Directory objects to search?

Start the MMC Active Directory Users and Computers snap-in. (Select Programs, Administrative Tools, Active Directory Users and Computers from the Start menu.)

Right-click the container, and select Properties.

Select the Group Policy tab.

Select the Group Policy Object, and select Edit.

Select the User Configuration branch, and expand Administrative Templates, Desktop, Active Directory.

Double-click Maximum size of Active Directory searches.

Select Enabled, and set the number (e.g., 20000), as the Screen shows.
Click here to view image

Click Apply.

Click OK.

Close the Group Policy Editor.

Start regedit.

Go to the HKEY_CURRENT_USERSoftwarePoliciesMicrosoft registry entry.

From the Edit menu, select New, Key.

Enter

Windows

Select the Windows key, and from the Edit menu, select New, Key.

Enter

Directory UI

Go to the Directory UI key, and from the Edit menu, select New, DWORD Value.

Enter

QueryLimit

and press Enter.

Double-click the new value, and set the decimal value.

Click OK.

Close the registry editor.