program SingleInstExample; {$I jcl.inc} uses JclAppInst, // Added JclAppInst unit Forms, SingleInstDemoMain in 'SingleInstDemoMain.pas' {Form1}; {$R *.RES} {$R ..\..\..\source\windows\JclCommCtrlAsInvoker.res} begin JclAppInstances.CheckSingleInstance; // Added instance checking Application.Initialize; Application.CreateForm(TForm1, Form1); Application.Run; end.