Please uninstall it and reinstall the last version of Remote Desktop Connection Manager from Microsoft to have a try. And for "unable to enumerate remote sessions" error, I found a similar case that might be helpful, it indicates that we must run the application with administrator permission on...
It appears to install OK but when i look in the Windows Features to turn it on or off the Remote Server Administration Tools option does not show in there. When i look in installed Windows updates the update does not show in there as being installed. I am running a fully licensed ...