I installed TeamCity locally on my Windows 8 machine. When I open TeamCity via my browser it shows 0 agents. When I look at the agents, I see 1 agent disconnected with a message that it unregistered itself and the message "will update".
I wait but nothing happens.
I checked the log file in C:\TeamCity\buildAgent\logs\teamcity-agent.log
and saw that message "Upgrade call received from the build server".
I then checked upgrade.log
in the same log folder, and saw the message Failed to stop TeamCity build agent service via net.exe
I had installed the TeamCity service and build agent using a user account (aka not SYSTEM).