I needed to connect remotely via Remote Desktop to a Windows Server 2012 machine.
I received an rdp file that was configured to use an RD Gateway server:
However when trying to connect from my Windows 7 laptop (x64) machine, I got the following error message:
One of the lesser known features of VMware ThinApp is that you can supply a Virtual Computer name.
This is documented as follows in the package.ini reference guide:
The VirtualComputerName parameter determines whether to rename the computer name, to avoid naming conflicts between the capture process and the deployment process.
Some applications use the computer’s name as a unique identifier, rather than using the user name. In a single-user-per-computer environment, this strategy works well.
However, in a Multi User environment such as Citrix XenApp or Microsoft’s Remote Desktop Services (Terminal Server), all connected users report the same computername.
If the application relies on unique computernames to handle tasks such as file and record locking, then the application will fail.
We can however set an Application Compatibility Flag in the registry to return the username instead of the computername.
To demonstrate this behaviour I wrote a small Test Application called TestAppCompatFlags.exe.
Scanners attached to client machines can be used from within a Citrix XenApp session via a mechanism called Twain Redirection.
For this mechanism to work correctly the file twain_32.dll must be present in the Windows directory.
On Windows 2008 this dll should be copied from winsxs (side by side) to the windows directory as described in CTX123981.
On Windows 2003 the dll is already in the correct directory, however applications that are not Terminal Server Aware cannot find this dll because the Windows directory is redirected to the user profile. Citrix recommends copying twain_32.dll to each user’s profile directory but this will take up unnecessary space.
So what alternatives do we have?
Today I troubleshooted an old DOS application that needed to run on a 32 bit Citrix XenApp Server. The last time I saw an actual DOS application in a production environment must be years ago.
When starting the application, the WOW subsystem (NTVDM) crashed with the message: “NTVM encountered a hard error.”:
After spending some time troubleshooting I remembered a similar issue from a few years ago where a DOS application worked fine from the Console but refused to work from an RDP or ICA session.