I have been using Full Desktop’s inside of XenApp forever. Lately I have been working on a project where I will be using only published apps. We are a CSP and a managed service provider who uses LabTech (Now ConnectWise Automate) to control all of our systems. LabTech uses a great remote access product called ScreenConnect to connect to the systems. All of this works flawlessly inside of a full desktop. However, when I published LabTech as a seamless app (LTClient.exe), everything seems to work fine except for ScreenConnect. I got a great Citrix engineer on the line who actually used all of the collected data I uploaded and troubleshot the issue. ConnectWise is actually a “ClickOnce” application which leverages dfsvc.exe to install and launch ScreenConnect. You can read this super exciting article on ClickOnce applications here.
Technically Citrix, nor Microsoft support any of these ClickOnce applications. Kudos on the Citrix engineer for continuing to work the issue with me, even though this is true. Luckily I already built a 2012R2 RemoteApp environment and was able to get this working to show Citrix this was not an application issue, but a Citrix seamless app issue. During troubleshooting he pointed me to this interesting article on ClickOnce and XenApp 6.5 here. I’m on 7.6 LTSR CU3, but still a good article on how this stuff works.
Anyway, after looking at the procmon information in the ticket, he quickly found that in the working scenario dfsvc.exe was calling ScreenConnect.WindowsClient.exe, where the seamless app was not. His “solution” was to simply run dfsvc.exe before calling LTClient.exe. Not really a “fix” but hell, it worked! So, I created a simple powershell script.
start-process "C:\Program Files (x86)\LabTech Client\LTClient.exe"
Lastly, I added dfsvc.exe to LogoffCheckSysModules per this CTX article.