С Windows 2003 на 2008R2 "Because of a security error, the client could not connect to the remote computer." : Windows

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Remote Desktop Disconnected
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Because of a security error, the client could not connect to the remote computer. Verify that you are logged on to the network, and then try connecting again.
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OK Help
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1) The security settings in general may be too strict to allow the client on the device to connect, lower them to allow it.

a. Navigate to Start > Administrative Tools > Remote Desktop Services > Remote Desktop Session Host Configuration.

b. With RD Session Host Configuration selected view under Connections.

c. Right click RDP Listener with connection type Microsoft RDP x.y and choose Properties.

d. In general tab of properties dialog box under Security, select RDP Security Layer as the Security Layer.

e. Click OK

Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM
On the Registry menu, click Export Registry File.
Type exported- Certificate in the File name box, and then click Save.

NOTE: If you have to restore this registry subkey in the future, double-click the Exported-parameters.reg file that you saved in this step.
Right-click each of the following values, click Delete, and then click Yes to confirm the deletion:

Certificate
X509 Certificate
X509 Certificate ID
X509 Certificate2
Quit Registry Editor, and then restart the server.

OlegON ➤ Хм, а как на 2008 выставить старый режим? .