Inno Setup: Close installer wizard if file exists in the program's folder

Question

I am trying to create an installer that is a Demo installer that if it detects the file close.txt in the programs folder then it closes the wizard or aborts ins

Answer 1

Test for the file existence in InitializeSetup event function and return False, if it exists.

[Setup]
DefaultDirName={autopf}\My Program

[Code]
function WasMyProgramEverInstalled: Boolean;
begin
  Result := FileExists('{#SetupSetting("DefaultDirName")}\close.txt');
end;

function InitializeSetup: Boolean;
begin
  Result := True;
  if WasMyProgramEverInstalled then
  begin
    MsgBox('Some message', mbError, MB_OK); { Optionally }
    Result := False;
  end;
end;

Note that if the installer allow customizing an installation path, you won't know it, when re-running the installation after uninstallation. So this won't work.