This indicates that the thread exited on its own before receiving the "detach" packet. The client should follow by sending a "release" packet; see [[#Exiting_Threads|Exiting Threads]], below.
Detaching from a thread causes all breakpoints, watchpoints, and other debugging-related state to be forgotten.
If the client sends a <code>"detach"</code> packet to a thread that is not in the <b>Running</b>, <b>Paused</b>, or <b>Exited</b> state, the actor sends an error reply of the form: