Environment: Windows 2008 R 2 VLV Programming via System.DirectoryService / c# / .Net 4.0 Active directory "Virtual List View" is slow, even I have set search-flags for CN in AD schema to 103 value. Reference: http://msdn.microsoft.com/en-us/library/windows/desktop/ms679765(v=vs.85).aspx For 200,000 objects in AD, searching with (cn=user_1111*) returning 111 objects takes 1:10 (mm:ss) to 2:10 (mm:ss) Too Bad. Similarly for searching with (cn=user_11111) returning 1 objects takes 1:30 (mm:ss) Too Bad. Secondly even the count is less then 10,000, still the approximate total record count is wrong. Looks like Indexes are not working....!!! According to Joe Richards, if index are not found then sort is performed, that can be one reason...In my case it should not because indexes are there Reference: http://www.winvistatips.com/re-virtual-list-view-and-critical-extension-unavailable-exception-t688822.html Anybody have programmed VLV via c#? Any tips on performance tuning of VLV??