>Is there a simple way to prevent multiple launches, or do I have to create a process that can check if the program is running?

For testing, build an Executable of this code (not in interactive mode).

As commented in a previous message to George Tasker, the mutex object is automatically released by the system when the application exit.

*-- Code Start
#define ERROR_ALREADY_EXISTS 183

Declare Integer CreateMutex in win32api integer, integer, string
Declare Integer GetLastError in win32api

CreateMutex(0, 0, 'MutexTest');

if GetLastError() = ERROR_ALREADY_EXISTS
   MessageBox('Application ALREADY running', 0, 'Test Mutex')
else
   MessageBox('Application SUCESSFULLY running', 0, 'Test Mutex')
endif

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