Agent is locked error, help!

My automated deploy immediately fails with an "Agent is locked" error. How can I fix this?

BuildMaster locks agents to avoid corrupting them during updates by creating a file named "locked" in the same directory as the remote agent service executable (bmagent.exe) or under the \bin directory for the IIS hosted agent. In rare cases this "locked" file will not be removed when an update is complete. If the Server Overview page shows that the agent is available and updated to the newest version of BuildMaster's core and extensions, feel free to simply delete the "locked" file.