Stefan,
Are you still having this issue? It doesn't sound like it's related to Lion. Are you able to connect from another client (Windows, Mac pre-Lion, Linux) with the same settings? Did you execute "xhost +localhost"?

  1.  x2go Client on Mac OS X Lion (10.7) [Workaround] (Stefan Fritze)


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Message: 1
Date: Sat, 31 Dec 2011 14:20:08 +0100
From: Stefan Fritze <stefan73er@e-postkasten.de>
To: x2go-user@lists.berlios.de
Subject: [X2go-User]  x2go Client on Mac OS X Lion (10.7) [Workaround]
Message-ID: <C5C07BE5-4FE1-4736-93F3-226E5018853F@e-postkasten.de>
Content-Type: text/plain; charset="iso-8859-1"

Dear all,

i've updated to MacOS X Lion and get the known Problem that "Rosetta" is needed.

I tried the Workaround

>
> Hello x2go mac os lion users, here is a workaround for using x2go client on os x lion:
>
> 1. Download and install OpenNX Client for Mac. (http://sourceforge.net/projects/opennx/)
> 2. Inside the opennx...dmg right click the OpenNX.pkg and click "show package content"
> 3. Doubleclick Contents/Archive.pax.gz
> 4. Go inside Archive/Library/OpenNX
> 5. Copy "bin" + "lib" + "share" to your clipboard (cmd-c)
> 6. Go to your x2goclient.app
> 7. Right click the x2goclient.app and click "show package content"
> 8. Go to "Contents" folder
> 9. Paste your clipboard inside this folder
> 10. Copy the content inside the "bin" folder to the "exe" folder (nxproxy will be overwritten)
>
> Now you can start x2goclient and connect to your server. If you get this error: "Invalid MIT-MAGIC-COOKIE-1 key" click on X11, start a terminal an type >"xhost +localhost".
>
> Regards
>
> Stephan Diehl
> Gesch?ftsf?hrer
>
> Open Solutions GmbH & Co. KG
> Luisenweg 109
> 20537 Hamburg
>

and the error message went away. But i still can't connect to my x2go server. Aber i type in my username and password it shown "connecting" and the x2go client freezes and after some time   (more or less a minute)  the x2go window is closed and a mac system message says the application was closed and i can show the detail information of the problem or send a report to apple.

Does anyone else have this problem? and is there a solution?

Best Regards

Stefan