Determines whether a script is allowed to run again when it is already running.
If the parameter is omitted, it defaults to Force. To change this behavior, specify one of the following words:
Force: Skips the dialog box and replaces the old instance automatically, which is similar in effect to the Reload function.
Ignore: Skips the dialog box and leaves the old instance running. In other words, attempts to launch an already-running script are ignored.
Prompt: Displays a dialog box asking whether to keep the old instance or replace it with the new one. This is the default behaviour if this directive is not used.
Off: Allows multiple instances of the script to run concurrently.
This directive is ignored when any of the following command line switches are used: /force /restart
Like other directives, #SingleInstance cannot be executed conditionally.
Previous instances of the script are identified by searching for a main window with the default title. Therefore, a previous instance may not be found if:
At most one previous instance is detected and sent a message asking it to close. Therefore, the following additional limitations also apply:
#SingleInstance Offmode), the topmost matching instance is sent the message, and other instances are not considered.
If multiple instances of the script are started simultaneously, they may fail to detect each other or may all target the same previous instance. This would result in multiple instances of the script starting.