Because of error in data encryption, this session will end

[guest]

Q: users is unable to connect to the terminal server . The error message is below:

"Because of an error in data encryption, this session will end. "

A: This issue might be caused by the following facts:

- The NIC on this problematic client
- A potential race condition between the Icaapi.dll and Rdpwsx.dll
dynamic-link libraries (DLLs) may cause the private certificate key on the
Terminal Services server not to be synchronized.

Given the current situation, let's try some steps to take care of the issue:

1. Please update the latest drivers for NIC

2. Modify the registry key, please backup the registry key before doing the
following steps:

2.1. Start Registry Editor.
2.2. Locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\TermService\Parameters

3. Under this registry subkey, delete the following values:
- Certificate
- X509 Certificate
- X509 Certificate ID

4. Quit Registry Editor, and then restart the server.

[chicagotech]

We have seen some cases like this one. It could be Large send Offload issue. To disable it open the Broadcom Advanced Control Suite and disable IPv4 Large Send Offload.

[chicagotech]

In some cases, you may try to modify the Advanced Flow, Flow Control, Checksum Offload and Speed & Duplex.

[blin]

I had a case. I can't access the server using RDC with the message: "Because of error in data encryption, this session will end", and the server is located in a remote site. What I found is that I can access it using remote desktop console to access the server and then disable IPv4 Large Send Offload. After that I can access it using RDC.

[chicagotech]

Also check this page: Large Send Offload Issue in windows Vista, 2008 and 7 - http://chicagotech.net/winissues/windows2.htm