Files that contain the .r03 file extension are normally associated with the WinRAR file archiving utility. This program is used to take large files or large batches of files and combine them into a single archive file.
When the WinRAR application is used to create an archive file, the archive can be split into separate volumes. This allows the file to be easily transferred via the Web or saved across multiple disks.
When an archive file is split, each volume of the archive is given its own file extension. The .r03 file extension is normally given to the third volume of the split file archive. In order to extract the contents of the archive, all of the volumes must be present.
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