Debug | Detach Debuggee
Click Detach Debuggee on the Debug menu to detach from the target application and leave it running.
Detaching from the target is supported under one of the following conditions:
(Microsoft Windows XP and later versions of Windows) You are debugging a running user-mode target.
You are noninvasively debugging a user-mode target.
If you are debugging a live target on Windows 2000, the Detach Debuggee command is not available, because this version of Windows does not support detaching from a target process.
For more information about how to exit the debugger or detach from the target, see Ending a Debugging Session in WinDbg.