SQL instance is not reachable randomly

[Tabita]

Hello everyone, Actually first illustrate the environment:

• Windows 2008 R2 Standard 64Bit;
• Windows SBS 2003 domain with 25 user CAL;
• Windows 2003 Server with Terminal 6 user CALs;
• Management-based DSN.

From randomly and seemingly without any logic some clients cannot connect to the management and control of the DSN does not appear in the instance. What is really strange is that PC without changing anything in the morning do not go work in the afternoon and vice versa. There's not a logical sequence for if a PC is not working, clean everything off and restarting the various machines, they do not work while connected first. I thought there was a problem of number of licenses, but physically counting machines have arrived in 18 machines locally, and then we Terminal 5 sessions to 23, except that it should not even count the server 3 then we are out but in theory it is Cal User the problem should not exist. Please is really urgent.

[Beothuk]

when the client can not connect to management, and SQL Server instance, that error message is returned? Upgrades were performed? A little 'time ago I had a similar problem: I upgraded from a client version of SQL Server from SS2000 to SS2008 through the instance that manages the database management system (OS Windows Server 2003). So I am looking for this also if anybody has any suggestion on the same so please help me.

[Leoniee]

After the upgrade some users began to complain of problems and slow connection ... now the client to connect to SQL Server using the provider SQLNCLI10, whereas before using SQLOLEDB. After many tests I concluded that it was the network card: some network cards (typically older ones) have problems communicating with the provider SQLNCLI10 ... this is what has happened to me. Have you checked that the network is OK? Also check for the virus. So this is what I know about it and I hope that it will help you guys.

[Emily123]

In response to your questions: The error that appears from the ERP is a "Could not find the SQL instance contact your system administrator", unfortunately, being away from home when I can not connect to see the error. The server is brand new, delivered in December and therefore the installation is clean from scratch is the OS that was both SQL backupped from the old server and restore it again. Clients are all fairly recent, the oldest of 2008 are the most recent last year, and are configured with the default driver that SQL actually has always worked well, even on my other clients who have a similar configuration and management mederimo, without using the Client 2008.

[Emma.J]

I have also some information on the same I hope that it will help you. The antivirus is AVG IS Business Edition installed now for 5 years and updated constantly, before bringing the server AEVO also did all the updates possible via the integrated update of the SO (Small critical system that I do not like at all and preferred the old website). At first everything was working properly, but I can not understand why if they were not all connected, or who knows what other reason.