Hi, I have a TList which stores some objects. Now I have a function which does some operations on that list: function SomeFunct(const AIndex: integer): IInterface begin if (AIndex > -1) and (AIndex < fMgr.Windows.Count ) then begin if (fMgr.Windows[AIndex] <> nil) then begin if not Supports(TForm(fMgr.Windows[AIndex]), IMyFormInterface, result) then result:= nil; end; end else result:= nil; end; now, what is really strange is that accessing fMgr.Windows with any proper index causes EListError... However if i hard-code it (in example, replace AIndex with value 0 or 1) it works fine. I tried debugging it, the function gets called twice, with arguments 0 and 1 (as supposed). while AIndex = 0, evaluating fMgr.Windows[AIndex] results in EListError at $someAddress, while evaluating fMgr.Windws[0] instead - returns proper results ... what is even more strange, even though there is an EListError, the function returns proper data ... and doesn't show anything. Just info on two EListError memory leaks on shutdown (using FastMM) any ideas what could be wrong?! Thanks in advance michal