[Aristarh Dark]

Немного добавлю в код:

Код:

interface

uses
  SyncObjs,
...
implementation

var
  CriticalSection: TCriticalSection;

function GetMemo: String;
begin
  CriticalSection.Enter;
  try  //<------------------------------------------------
    if Form1.Memo1.Lines.Count>0 then
    begin
      Result:=Form1.Memo1.Lines[0];
      Form1.Memo1.Lines.Delete(0);
    end else Result:='';
  finally
    CriticalSection.Leave;
  end;
end;
...
initialization
  CriticalSection:=TCriticalSection.Create;

finalization
  CriticalSection.Free;