A RAR archive can be split into multiple parts, each contained in a separate file. This is typically used when storing the archive on removable media that are not large enough to store the archive as a single file. It is also often used on the internet so that if the archive becomes damaged while downloading, only the parts that are damaged need to be redownloaded and not the entire archive.

You can usually recognize multi-part archives by the suffix "part" included in the file name of each part of the archive. For example, a multi-part archive named "Example Archive" consisting of 3 parts would typically be stored in files with names "Example Archive.part1.rar", "Example Archive.part2.rar" and "Example Archive.part3.rar". Sometimes different file name extensions for each part may also be used instead of the "part" suffix: only the first part of the archive then has the file name extension ".rar" while the second part has extension ".r00", the third ".r01" and so on. For example, the multi-part archive "Example Archive" may also be stored in files with names "Example Archive.rar", "Example Archive.r00" and "Example Archive.r01".

To expand a multi-part archive with RAR Expander you should always select the first part of the archive to start expanding from. Otherwise not all files of the archive will be expanded and the expansion process may result in errors.

After expanding a part of a multi-part archive RAR Expander may ask you to locate the next part of the archive. If you downloaded the parts from the internet and stored them all in the same folder, RAR Expander will usually not need to ask you to locate each part but will automatically locate and expand them all. In other cases RAR Expander will show a file dialog telling you the file name it expects the next part to have and asking you to locate this file. If the parts of the archive are stored on different removable media, you should then eject the current medium, insert the one containing the next part and select that part in the file dialog.