a00

.a00Archive File

Robert K. Jung · 1990

Developer
Robert K. Jung
Category
Archives
MIME Type
application/x-arj
First Released
1990
Open Format
No
File Signature
Not applicable as it's a segment, not a self-contained format signature.
At a Glance
.a00
Archive File

A segment of a larger, split archive file, requiring all parts to be reassembled.

Reviewed on May 22, 2026
Compression
Varies (depends on original archive)
Transparency
No
Editability
Low (requires extraction first)
Best for
Split archive segments

Key Features

  • Part of a split archive
  • Sequential numbering indicates order
  • Requires all parts for extraction
  • Commonly associated with older archiving tools

Best For

  • Breaking large archives into manageable chunks
  • Distributing files via older media like floppy disks
  • Ensuring compatibility with legacy archiving software

Less Ideal For

  • Modern large file sharing where cloud services are available
  • Single, self-contained archive needs
  • Archiving that requires strong modern compression algorithms
  • Applications that don't support split archives

Common Use Cases

  • Distributing large files across multiple floppy disks
  • Sending large files via email when size limits apply
  • Archiving large datasets that exceed single-file limits
  • Preserving historical software distributions

How to Open It

  1. Ensure all sequential parts (.a00, .a01, etc.) of the archive are downloaded to the same folder.
  2. Use an archive utility like 7-Zip, WinRAR, or PeaZip that supports multi-part archives.
  3. Open the first file in the sequence (e.g., the .a00 file) with the chosen utility.
  4. The utility should automatically detect and process the subsequent parts to extract the original content.

What is a .a00 file?

The .a00 file extension typically represents a split or multi-part archive file. These archives are created when a single archive is too large to be stored or transmitted as one piece. The original archive is broken down into smaller segments, each with a sequential file extension like .a00, .a01, .a02, and so on. To use the files contained within, all parts must be present and in the correct order, and then opened with an archive utility that supports split archives. This method was common for distributing large files before widespread high-speed internet access.

Programs That Open .a00 Files

PlatformProgram
Windows7-ZipFreeOfficial
WinRARPaidOfficial
PeaZipFreeOfficial
macOSThe UnarchiverFree
KekaPaidOfficial
Linux7-Zip (p7zip)FreeOfficial
PeaZipFreeOfficial
AndroidRARPaidOfficial
ZArchiverFree
iOSiZipFree
Documents by ReaddleFree

How to Convert .a00 Files

FormatMethod
.ZIPExtract all parts, then re-archive as ZIP using 7-Zip or WinRAR
.RARExtract all parts, then re-archive as RAR using WinRAR

Common Problems with .a00 Files

⚠️ Missing one or more archive parts.
Ensure all sequential files (.a00, .a01, etc.) are downloaded to the same directory before attempting to open.
⚠️ Archive fails to extract.
Verify that all parts are error-free (try re-downloading) and that you are using compatible software that supports the original split archive format (e.g., ARJ).
⚠️ Trying to open only the .a00 file without other parts.
You must open the first part of the sequence (usually .a00) with a decompressor that understands split archives. The decompressor will then find and use the other parts.

Frequently Asked Questions

What is a split archive?

A split archive is a single archive file that has been divided into multiple smaller parts. This is typically done to make it easier to transfer large files, especially on older systems with size limitations.

Do I need special software to open .a00 files?

Yes, you need archive software that supports multi-part or split archives, such as 7-Zip, WinRAR, or PeaZip. Crucially, you must have all the sequential parts of the archive available.

Can I open just the .a00 file?

While you initiate the opening process with the .a00 file, your archive software will need to access all subsequent parts (.a01, .a02, etc.) to successfully reconstruct and extract the original contents.

Technical Details

The .a00 file is not a standalone archive format but rather a segment of a larger archive that has been divided. It's often associated with older archiving tools like ARJ, where files exceeding a certain size limit were split into sequentially numbered parts. To reconstitute the original archive, all sequential parts (.a00, .a01, etc.) must be present and processed by compatible decompression software.

Did You Know?

The concept of splitting archives was essential for distributing large software packages on floppy disks.
While .a00 is commonly associated with ARJ archives, other formats could also use similar sequential splitting conventions.

Security Information

Like any archive file, .a00 segments can contain malicious software. Always scan downloaded files with reputable antivirus software before opening them, especially if the source is untrusted.

Related Extensions