Track access violation in Delphi -

i'd track access violation error triggered.

threads created , perform jobs. suspect them access vcl or variables without "synchronise". madexcept report show access violation occurs on form close (form1.close;), no more precision.

i've got many lines of codes (around 100.000).

what should avoid spending time ? i've checked "range checking" in debugger option.

many thanks

if want know, can build project debug dcu's , put breakpoint before point exception occurs.

now can jump vcl code , see goes wrong.

but access violations in close or destructors because of double freeïng of object. example, free component freed form (because owned form).