In the SQL Server 2005 upgrade advisor help file it states the following...
"Upgrade Advisor detected an older version of MDAC. MDAC versions before MDAC 2.8 SP1 do not support named instances. To allow application connections to named instances, upgrade to MDAC 2.8 SP1."
I've installed our application which uses ADO (not ADO.NET) to connect to an SQL Server named instance on a client machine. Our application installs MDAC 2.6. Therefore on older machines such as Windows 95 MDAC is upgraded to 2.6. Our application can still connect to the named instance without MDAC 2.8 SP1 being present.
Is this statement in the upgrade advisor entirely true or am I misunderstanding what it means
Thanks.

MDAC and SQL Server 2005
Richard Guo
Hope this helps.
Regards
Uwa
Reza Chitsaz - MSFT
However, if you have deployed clients and you are simply upgrading the server to SQL Server 2005 there is no requirement to upgrade from MDAC to SQL Native Client.
tmenier
ODBC connectivity to SQL Server 2005 on 64bit is supported either via MDAC or the new SQL Native Client ODBC driver (which offers better performance and features in some areas).
And by the way, MDAC 28 is part of the Windows 2003 and XP operating systems so you will not need to install this.
Hope this helps.
Uwa
Coding_Freak
I will certainly check out SQLNCLI though as that sounds interesting.
Thanks
smeets116
I've got a client machine here with MDAC 2.6SP2 installed where our application can perfectly connect to my server which is running SQL Server 2005 in a named instance.
Thanks
Ramone
For better performance and if you use the new data types in SQL Server 2005 or other cool new features (MARS, notifications etc), I would recommend you use the new SQLNCLI (SQL Server native client) which has the equivalent of the OLEDB provider and ODBC Driver in one DLL package. It has it's own MSI installer that is on the Server media. Please see http://support.microsoft.com/ kbid=910016 for more info
KC-Jenner
Thanks guys for good info.
I have a similar question. We have an application (C++ and built in 32bit) using ODBC driver to connec to SQL Server 2000 or Oracle 9 server. Can our application connect to SQL Server 2005 (64bit) without modification We dont mind to install MDAC 2.8SP1 on the SQL Server 2005 (64bit) machine.
I would appreciate your help.
John