First the problem: Since I applied the [latest patch to SQL Server 2008 R2](https://support.microsoft.com/en-us/help/3146034/intermittent-service-terminations-occur-after-you-install-any-sql-serv) (released on March 3, 2016) that should have taken my server to build 10.50.6542 I can't connect anymore. This patch is to provide support TLS 1.2.

The error I'm getting (when attempting to connect using a client tool directly in the server) is 

```
"A connection was succesfully established with the server, but then an error occurred during the pre-login handshake"

```

[![enter image description here](https://i.stack.imgur.com/7btXc.jpg)](https://i.stack.imgur.com/7btXc.jpg)

The server is a Windows Server 2012 R2 and is running NET Framework 4.6.1 (some posts point to older version of .NET framework causing this problem, but this is not my case).

I tried to run the following packages to see if this would fix...

* SQL Server Native Client (x86 and x64)
* Hotfix rollup 3106993 for the .NET Framework 2.0 SP2 in Windows Server 2012 R2 and Windows 8.1
* Hotfix rollup 3106994 for the .NET Framework 4.0 in Windows
* Hotfix rollup 3099845 for the .NET Framework 4.5.2, 4.5.1, and 4.5

... None of these were necessary, and nothing helped...

Has anybody experienced this? Any ideas or suggestions?

Thanks!

**One Update 24 hours later**
I inspected the SQL Server error log looking for entries that include only a Start, 5 failed login attempts and a stop. From all the messages in that time-frame (107 entries in total) the only message that includes anything like an error is 

```
 The SQL Server Network Interface library could not register the Service Principal Name (SPN) for the SQL Server service. Error: 0x2098, state: 15. Failure to register an SPN may cause integrated authentication to fall back to NTLM instead of Kerberos. This is an informational message. Further action is only required if Kerberos authentication is required by authentication policies.

```

This message though… has been reported on server startup even before I applied the patch so I am 100% confident that it is a red herring. No logs are inserted in the SQL Server error log as a result of the failed login attempts.

**Another Update**

Based on suggestions I got from people here, I downloaded and installed the latest version of SSMS (17.3) on the server. When I tried connecting this time, I got a different error so it seems I'm moving further, but I'm not there yet.

[![enter image description here](https://i.stack.imgur.com/8mIEi.jpg)](https://i.stack.imgur.com/8mIEi.jpg)

So it seems that it is true that old versions of SSMS do target .net 3.5 and even if you have newer versions of the .net framework the client connections will not work, the question is now why is that I still get this "No process is on the other end of the pipe", even when most of the client components have been updated.

**Some more things I have investigated (and discarded)**

* The “client protocol” order in SQL Server Configuration Manager seems to be the correct one, as TCP/IP is at the top. This was suggested as a possible cause of trouble, but in my case it is all appropriately configured (apparently)

[![enter image description here](https://i.stack.imgur.com/jjE3s.jpg)](https://i.stack.imgur.com/jjE3s.jpg)

* Tried to install “Microsoft ODBC Driver for SQL Server” as suggested in the [TLS 1.2 support for Microsoft SQL Server](https://support.microsoft.com/en-us/help/3135244/tls-1-2-support-for-microsoft-sql-server) but that didn’t make a difference either. After installing, the error message is the same
* Tried adding the registry keys at HKEY\_LOCAL\_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2 (also as suggested in the [same article](https://support.microsoft.com/en-us/help/3135244/tls-1-2-support-for-microsoft-sql-server)). Same error…