If you are trying to this specific file and encountering errors:
If you are the one creating these parts for ELO's MP3 collection: and select the music files. Click Add . ELO_MP3.part21.rar
If you are preparing or managing this file, here is how the "Solid" feature applies: If you are trying to this specific file
In file sharing and archiving, a "solid" feature (or Solid Archive) is a specific compression method used by tools like WinRAR to treat multiple files as one continuous data stream. Understanding Solid Archives for ELO_MP3 Understanding Solid Archives for ELO_MP3 : The "Solid"
: The "Solid" feature makes all files in the archive interdependent. Because part21.rar is just one piece of the chain, you cannot extract its contents unless you have all preceding parts (1 through 20) and the subsequent parts.
: By using the Solid Archive option, WinRAR can achieve significantly better compression. This is especially effective for a discography like ELO's, where many songs share similar data patterns, frequencies, and metadata structures.