: Many mystery RAR files require a password found in metadata, hexadecimal code, or hidden in an image associated with the file's source.
: If the file won't open, the "piece" you need to put together might be a corrected hex header (changing the first few bytes to 52 61 72 21 1A 07 00 for RAR 5.0). 21538.rar
If this is a private file or a specific puzzle you are working on, "putting together a piece" usually involves one of the following steps: : Many mystery RAR files require a password