In Adobe Reader Acrobat DC, when I try to copy a text from PDF file (in Russian) I get something like this: Íåêîòîðûå çàäà÷è êëàññè÷åñêîé ìåõàíèêè (it is not in Russian). But it must look like this: Некоторые задачи классической механики. This error occurs sometimes for some PDF files in Russian language. For other files, also in Russian, copying is correct. Is there a way to get rid of this error for all files in Russian? I had the impression that earlier versions of Adobe Reader handled the Russian text better (for example, Adobe Reader XI 11.0.0 Rus). Moreover, Foxit Reader works with all such files quite correctly (files that are not processed in Adobe Reader Acrobat DC are quite easy to process in Foxit Reader).