Remote Access to VirtualBox with Remote Display enabled: Multiple issues with Windows remote desktop client

* Issue #1 *

I have configured an external simple authentication in VirtualBox. KRDC (rdesktop) is able to connect to the guest OS without a problem with configured user/password. However I cannot connect from neither Win XP remote desktop client nor Win7 remote dektop client. Connection seems to be established but on the Windows side I'm getting an errors saying:

"Your Remote Desktop session has ended. Your network administrator might have ended the connection. Try connection again, or contact technical support for assistance".

The other message is saying "This computer might be low on virtual memory. Close your other programs, and then try connecting to the remote computer again. If the problem continues...."

A second message doesn't make any sense. The source system has no running processes and has 2Gb of RAM and 2Gb of virtual.

VirtualBox log file at the same time contains this:

01:08:15.066 VRDP: New connection:
01:08:15.066 VRDP: Negotiating security method with the client.
01:08:15.102 VRDP: Methods 0x0000001b
01:08:15.103 VRDP: Channel: [rdpdr] [1004]. Accepted.
01:08:15.103 VRDP: Channel: [rdpsnd] [1005]. Accepted.
01:08:15.103 VRDP: Channel: [drdynvc] [1006]. Accepted.
01:08:15.103 VRDP: Channel: [cliprdr] [1007]. Accepted.
01:08:15.374 VRDP: Client seems to be MSFT.
01:08:15.374 VRDP: Logon: --computer_name_here--- (10.0.2.15) build 6001. User: [] Domain: [] Screen: 0
01:08:15.374 AUTH: User: []. Domain: []. Authentication type: [External]
01:08:15.375 AUTH: external authentication module returned 'access denied'
01:08:15.375 AUTH: Access denied.
01:08:15.375 VRDP: Connection closed:
01:08:15.375 VRDP: Logoff: --computer_name_here--- (10.0.2.15) build 6001. User: [] Domain: [] Reason 0x0001.

Any ideas how to make it work?

Note1: it is working when authentication is disabled. However this is not acceptable. Note2: Same error message appears even when I login as one of the configured on VirtualBox side users and provided a user name in advanced settings for remote desktop connection.

* Issue #2 *

Even Windows remote desktop client get connected to the Remote display provided by VirtualBox a screen doesn't update at all. I need to minimize/maximize to see what is on the screen at the moment.

Any ideas how configure windows client to avoid this problem?

To get Windows Remote Desktop Client (certainly the version included with Windows 7, haven't tested others) to connect to VirtualBox VRDP sessions, you need to tick the "Allow me to save credentials" box in the Options drop-down, then connect as normal.

You don't necessarily have to save the credentials, you just need to have that box ticked. I'm not sure if it's something to do with how the VRDP server reads the connection info or something to do with how MSTSC sends it.

For your issue #2, it sounds like a bandwidth issue. Click the "Display" tab and choose a lower resolution and lower colour depth. You can also click the "Experience" tab and play with those settings. Do they make any difference? Are you connecting over a LAN or over the Internet?