Hi,

I'm running X2Go Client 4.1.0.0 on Windows Server 2012 R2 for connecting to X2Go Server 4.0.1.22 on Ubuntu 14.04. This usually works flawlessly. Since about 4 months ago, however, X2Go Client *sometimes* fails to fully establish the session. (Sometimes means that it happens quite unregularly; which makes it hard to reproduce. But when it happens, it can last from 5 minutes up to around 30 minutes until connections are successful again.) In these cases X2Go Client actually connects to the server, but the startup of VcXsrv fails, so X2Go Client subsequently terminates the connection. I attached the log output of VcXsrv below. I suspect that in the cases when the connection fails to fully establish, VcXsrv for some reason doesn't manage to find a free display number. Maybe this is due to the fact that on the Windows server several users are logged in simultaneously and use X2Go Client. Another guess is that VcXsrv might not like the fact that the Windows server has two IPv4 addresses. Does anyone have a clue what could be the reason for it? Or where I could find further information on these error messages? Thank you for any hint.

On the client side, the following is logged in C:\Users\<username>\AppData\Local\Temp\VCXSrv.0.log when the connection fails:

-- Welcome to the VcXsrv X Server Vendor: The X2Go and Arctica Projects Release: 1.17.0.0

OS: Windows NT 6.2 build 9200 (WoW64) Contact: https://github.com/ArcticaProject/vcxsrv

_XSERVTransSocketCreateListener: failed to bind listener _XSERVTransSocketINETCreateListener: ...SocketCreateListener() failed _XSERVTransMakeAllCOTSServerListeners: failed to create listener for inet DefineSelf - d16s003 has IPv6 addresses... ::1 LoadPreferences: C:\Users\<username>\AppData\Roaming/.XWinrc not found LoadPreferences: Loading P:\X2Go\V4_1_0_0\x2goclient\vcxsrv\system.XWinrc Warning: Locale not supported by X, falling back to 'C' locale. wglwrap: Can't resolve "wglGetExtensionsStringARB" (EE) AIGLX: Won't use generic native renderer as it is not accelerated (II) AIGLX: Loaded and initialized swrast (II) GLX: Initialized DRISWRAST GL provider for screen 0 winBlockHandler - pthread_mutex_unlock() winInitMultiWindowWM - Could not open display, try: 1, sleeping: 5 winInitMultiWindowWM - Could not open display, try: 2, sleeping: 5 winInitMultiWindowWM - Could not open display, try: 3, sleeping: 5 winInitMultiWindowWM - Could not open display, try: 4, sleeping: 5 winInitMultiWindowWM - Could not open display, try: 5, sleeping: 5 winInitMultiWindowWM - Failed opening the display. Exiting. (EE) Server terminated with error (1). Closing log file.

In the case of successful connection, the log output looks like:

-- Welcome to the VcXsrv X Server Vendor: The X2Go and Arctica Projects Release: 1.17.0.0

OS: Windows NT 6.2 build 9200 (WoW64) Contact: https://github.com/ArcticaProject/vcxsrv

DefineSelf - d16s003 has 2 usable IPv4 interfaces... addresses 10.36.2.103 10.36.18.106 DefineSelf - d16s003 has IPv6 addresses... ::1 LoadPreferences: C:\Users\<uername>\AppData\Roaming/.XWinrc not found LoadPreferences: Loading P:\X2Go\V4_1_0_0\x2goclient\vcxsrv\system.XWinrc Warning: Locale not supported by X, falling back to 'C' locale. wglwrap: Can't resolve "wglGetExtensionsStringARB" (EE) AIGLX: Won't use generic native renderer as it is not accelerated (II) AIGLX: Loaded and initialized swrast (II) GLX: Initialized DRISWRAST GL provider for screen 0 winBlockHandler - pthread_mutex_unlock() winClipboardThreadProc - DISPLAY=127.0.0.1:0.0

When I just start vcxsrv.exe, I'm getting the same messages. At times when connections fail:

-- Welcome to the VcXsrv X Server Vendor: The X2Go and Arctica Projects Release: 1.17.0.0

OS: Windows NT 6.2 build 9200 (WoW64) Contact: https://github.com/ArcticaProject/vcxsrv

_XSERVTransSocketCreateListener: failed to bind listener _XSERVTransSocketINETCreateListener: ...SocketCreateListener() failed _XSERVTransMakeAllCOTSServerListeners: failed to create listener for inet DefineSelf - d16s003 has IPv6 addresses... ::1 LoadPreferences: C:\Users\<username>\AppData\Roaming/.XWinrc not found LoadPreferences: Loading P:\X2Go\V4_1_0_0\x2goclient\VcXsrv\system.XWinrc Warning: Locale not supported by X, falling back to 'C' locale. (EE) AIGLX: No native OpenGL in modes with a root window (II) AIGLX: Loaded and initialized swrast (II) GLX: Initialized DRISWRAST GL provider for screen 0 winBlockHandler - pthread_mutex_unlock()

At times when connections work:

-- Welcome to the VcXsrv X Server Vendor: The X2Go and Arctica Projects Release: 1.17.0.0

OS: Windows NT 6.2 build 9200 (WoW64) Contact: https://github.com/ArcticaProject/vcxsrv

DefineSelf - d16s003 has 2 usable IPv4 interfaces... addresses 10.36.2.103 10.36.18.106 DefineSelf - d16s003 has IPv6 addresses... ::1 LoadPreferences: C:\Users\<username>\AppData\Roaming/.XWinrc not found LoadPreferences: Loading P:\X2Go\V4_1_0_0\x2goclient\VcXsrv\system.XWinrc Warning: Locale not supported by X, falling back to 'C' locale. (EE) AIGLX: No native OpenGL in modes with a root window (II) AIGLX: Loaded and initialized swrast (II) GLX: Initialized DRISWRAST GL provider for screen 0 winBlockHandler - pthread_mutex_unlock()

Best, Andy