I'm setting up a new Citrix Xenapp 7.9 2012 server with Citrix roaming profiles. I'm adding users and all is well except for one extension. As soon as provisioning file is loaded, .net runtime error: Application: 3CXWin8Phone.exe Framework Version: v4.0.30319 Description: The process was terminated due to an unhandled exception. Exception Info: exception code c0000005, exception address 68A22C80 and also Faulting application name: 3CXWin8Phone.exe, version: 14.0.49169.0, time stamp: 0x56cb2e90 Faulting module name: VCEWindows8Agent.dll, version: 0.0.0.0, time stamp: 0x56cb192b Exception code: 0xc0000005 Fault offset: 0x00112c80 Faulting process id: 0x4344 Faulting application start time: 0x01d20adae7b67446 Faulting application path: C:\ProgramData\3CXPhone for Windows\PhoneApp\3CXWin8Phone.exe Faulting module path: C:\ProgramData\3CXPhone for Windows\PhoneApp\VCEWindows8Agent.dll Report Id: 2c76224a-76ce-11e6-80f6-0050568289e0 Faulting package full name: I have tried loading the config file in other windows user profiles with the same outcome. I have another test 2012 server (not citrix) and it loads fine there. I have uninstalled and reinstalled 3CXwin8phone on the affected Citrix server. We have deleted and recreated the extension with limited configuration in 3CX server, but we cannot get it to work. 5-10 other extensions work fine it is just this one at this point. This one server does not like this one extension#. The same extension config can be loaded on Win7, and another 2012 non citrix server. To recap, this one extension will load anywhere else except this server. It is not limited to the one roaming user profile, it will fault in test user profiles on this server as well, even with admin rights. I've looked for places to delete possibly held data for this extension on the server to start fresh for this extension, but the only place i'm aware of is the user appdata folder where the xml config is held. I'm at a loss at this point.