There is an issue with the originally installed version of GoToAssist that caused the client machine to no longer show up on the list of available computers in the GoToAssist Expert software.
Uninstall any Citrix Programs
Open Regedit
Browse to HKEY/CURRENTUSER/SOFTWARE
Delete Citrix Folder
Go to gotoassist.com and login (see credentials page)
Download Unattended Installer (.msi) and run
You should see the computer show up on list now.