What is the R00 file format?
The .r00 file is part of the legacy multi-volume archive format developed by Eugene Roshal and distributed by RARLAB, one of the leading file compression software developers. It is a split RAR archive segment handled by applications such as WinRAR, 7-Zip, and PeaZip. The format is supported on Windows, macOS, and Linux.
In the legacy RAR naming scheme, a split archive always begins with a file named <name>.rar - that is the first volume and the entry point for extraction. The .r00 file is the second volume of the set, followed by .r01 as the third, .r02 as the fourth, and so on. All parts must be present in the same folder and opened in sequence for successful extraction; opening .r00 directly without the .rar first will produce an error in most archive tools.
This .r00/.r01/.r02 naming scheme is a legacy convention from WinRAR 2.x. WinRAR 3.0 and later switched to the clearer .part1.rar/.part2.rar/.part3.rar scheme, so .r00 files are most often encountered with older archives distributed online. Each volume carries a portion of the compressed data stream; the archive header, file list, and CRC32 checksums are stored in the first .rar volume.
Security & safety
RISK: MEDIUMA .r00 file is part of a RAR archive, which is a classic malware delivery wrapper: split multi-volume sets can bypass basic file-size or type filters. Scan the extracted contents before running anything. The split-file nature also introduces a completeness risk: if any volume is missing or corrupted, the entire archive cannot be extracted. WinRAR recovery records (if present in the archive) can repair a damaged volume. Be wary of .r00 files from untrusted sources, especially if the archive is password-protected.
Format details
in a nutshellPrograms that open R00 files
Windows3 apps
WinRAR
Paid Put ALL volumes (.rar, .r00, .r01 …) in one folder. Open or double-click the FIRST file (.rar) and click Extract. WinRAR reads the .r00/.r01 siblings automatically. 
7-Zip
Open-source With all parts in one folder, right-click the .rar (first part) > 7-Zip > Extract Here. 7-Zip handles legacy .r00/.r01 multi-volume sets. Free. 
PeaZip
Open-source Open the first .rar volume with all parts in the same folder; PeaZip extracts the full set. Free. 
macOS2 apps
The Unarchiver
Free Put all parts together and open the first .rar volume. The Unarchiver handles RAR4 multi-volume sets including legacy .r00/.r01 naming. 
Linux4 apps
File Roller
Open-source GNOME archive manager; open the first .rar with all parts present. Needs unrar backend. 
unrar (RARLAB)
Free Run 'unrar x archive.rar' in the directory containing all volumes - unrar reads .r00/.r01 automatically. Technical details
deep spec| Encoding | Binary, little-endian |
| Archive role | Second volume in a legacy RAR multi-volume set (the first numbered continuation after the primary `.rar` file) |
| Naming convention | First part: `<name>.rar`; subsequent parts: `<name>.r00`, `<name>.r01`, `<name>.r02`, …, `<name>.r99`, then `<name>.s00` etc. for very large sets |
| Compression algorithm | RAR proprietary LZSS + PPM; identical algorithm to the main `.rar` volume |
| Extraction requirement | All volumes must be present; extraction must start from the first `.rar` file - opening `.r00` alone fails |
| Integrity checking | Per-file CRC32 checksums stored in the `.rar` header volume; verified on extraction of each file |
| Encryption | AES-128 (RAR4) if the archive was created with a password; encryption state is inherited from the `.rar` header |
| Typical volume sizes | Set by the creator; common sizes are 10 MB, 50 MB, 100 MB, 700 MB (CD-size), 4.7 GB (DVD-size) |
| Recovery volumes | Optional `.rev` recovery volumes allow repair of one or more damaged segments in the set |
| RAR format generation | Legacy RAR4 multi-volume naming; WinRAR 3.0+ (2002) introduced `.part1.rar` / `.part2.rar` as the new default naming scheme |
| Archive header location | Contained only in the first `.rar` volume; the `.r00` continuation segment carries no independent archive header in most cases |
| Platforms | Windows, macOS, Linux (via WinRAR, 7-Zip, PeaZip, unrar CLI, Keka, The Unarchiver) |
| Released | ~1993 (RAR multi-volume split with .r00/.r01 naming from early WinRAR versions) |
| Latest version | Part of RAR4 format; modern WinRAR 3+ uses .part1.rar/.part2.rar naming instead |
| Specification | www.rarlab.com |
R00 conversions
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