Lock Symbol When Copy Smth

I got problem with copying file.Well, problem is described in topic title.Lock symbol in file icon.When I make a "New" contents, there is no lock symbol.But when i copy or cut out and paste file, there IS lock symbol.i will describe it in "Old" file.It happens sometimes and sometime it doesn't.It's pretty random.Lock symbol disappear when i copy and paste old file.Like Overwritting or changing name and pasting it.It's not very serious when i'm working with current account but when my computer crashes and can't boot normally..I will use temporary OS to solve problem but Temp OS can't access file with lock symbol.