One of the default settings for ControlUp versions v7.3 and previous was "Uninstall Agents automatically when not in use"
This is a legacy setting that will be disabled for new Organizations beginning in v7.4 going forward.
What is this setting for?
ControlUp has a very small footprint in your environment, and in early days it was even smaller.
This Feature was previously called "Temporary Agent Mode"
The way it works is if you have launched a Console and deployed Agents from the Console to your computers with Temporary Agent Mode enabled, where the Agent Service is installed with a "cuAgent.exe /temp" command line and the service Run type is set to "Manual". After you close your Console and the Agent has no connection to any ControlUp infrastructure components (environments with no Monitor installed for example) the Agent service will wait 5 minutes and then it will uninstall itself from the system.
Why this setting is a problem.
Now that we have an infrastructure footprint that monitors your environment 24/7/365 in order to upload Real Time activity to the Cloud for viewing as historical and analytical reports, the Temporary Agent never uninstalls itself because it has an "always on" connection to the ControlUp Monitor service.
Many environments have a regular reboot cycle for their systems. If you recall, the Temporary Agent service is installed with a Startup or Run type of "Manual" - so if the system reboots, the Agent service will not be started when system startup is complete.
When you try and connect to a system with a Temporary Agent installed and not running, you will see an error "Could not connect to net.tcp://<hostname>:40705/cuAgent. The connection attempt lasted for a time span or 00:00:00. TCP error code 10061: No connection could be made because the target machine actively refused it <IP Addr>:40705"
What is the fix for this problem?
The best fix for this issue is to simply Uninstall the ControlUp Agent from the Console. Uncheck or Disable "Agents will be uninstalled automatically when not used" and re-install the Agents on affected systems from the Console.