000 File Documentation

Summary

A .000 file is most often the first data segment of a CD or DVD disc image created by IsoBuster, a data-recovery tool, saved alongside a small .IBP or .IBQ header file. You open the matching .IBP in IsoBuster, not the .000 itself, and it reassembles the segments. The extension is ambiguous: .000 is also the generic first part of a split file from tools like HJSplit or 7-Zip, and occasionally a TrueCrypt/VeraCrypt volume. Its MIME type is the generic application/octet-stream.

Technical details

FeatureValue
Full nameIsoBuster Managed Image File (first segment)
File extension.000
MIME typeapplication/octet-stream
Format typeFirst/segment file of a split CD/DVD disc image
DeveloperSmart Projects (IsoBuster)
CategoryDisk Image Files
Companion header.IBP (or .IBQ for the compressed variant) — open this, not the .000
Sibling segments.001, .002, ... (all needed to rebuild the image)
Magic numberNone of its own — raw data segment (identity is in the .IBP)
Self-describingNo — a lone .000 cannot be mounted or extracted
Also used byGeneric split-file first part (HJSplit, 7-Zip); occasionally a TrueCrypt/VeraCrypt volume
Native toolIsoBuster (Windows, freemium — reads images free)
Other openersUltraISO, PowerISO; 7-Zip for split-archive .000 sets
Valid conversions.iso, .img, .bin/.cue (disc-image containers)
Safe to deleteOnly if you no longer need the disc image and have the original disc
Related extensions.ibp, .ibq, .iso, .img, .001, .bin, .cue

What is a .000 file?

A .000 file is, in its primary meaning, the first data segment of a CD or DVD disc image produced by IsoBuster, a Windows disc and hard-disk data-recovery tool from Smart Projects. When IsoBuster creates a “managed image”, it writes a small descriptor file (.IBP, or .IBQ for the compressed variant) plus the actual image data in one or more large segment files numbered .000, .001, .002 and so on. The number is just the order of the pieces, not a file type.

The .000 is not a defined, self-describing format with its own header. It is a raw slice of image bytes, so its content depends entirely on what disc was captured. That is the source of nearly all confusion around this extension, because the same .000 numbering is also used by unrelated tools. This article explains what an IsoBuster .000 actually is, how to tell it apart from the other things a .000 can be, and how to turn it into something usable.

The managed-image layout: header plus numbered segments

An IsoBuster managed image is a set of files that work together. The one you actually open is the .IBP (or .IBQ) descriptor: it holds the layout of the image and points IsoBuster at the numbered data segments. The .000 holds the leading bytes of the disc image, the .001 the next range, and so on. Splitting the data this way lets a multi-gigabyte image sit on size-limited storage; the classic reason is FAT32, which cannot hold a single file larger than about 4 GB.

disc_backup.IBP     small header/descriptor  <-- open THIS in IsoBuster
disc_backup.000     first data segment (leading image bytes)
disc_backup.001     next data segment
disc_backup.002     next data segment ...

Because the descriptor carries the structure and the segments carry the bytes, the .000 alone is not a mountable file. IsoBuster reads the .IBP, treats the segments as one continuous disc image, and lets you browse it, extract files from it, or save it out as a standard .iso.

Why a .000 has no signature of its own

The .000 is a plain byte range, so its first bytes are simply the first bytes of whatever it contains. If the captured disc used an ISO 9660 file system, the joined image contains the usual disc structures, but those are not at the start of the .000: the ISO 9660 volume descriptor, whose identifier reads CD001, sits at byte offset 0x8001 of the joined image, roughly 32 KB in, not at offset 0 of the first segment. So you cannot identify a .000 by a magic number the way you can a PNG or a ZIP. The reliable identifier is the companion .IBP file sitting next to it: if that is present, this is an IsoBuster image.

The ambiguity: three different things a .000 can be

The extension is genuinely overloaded, and telling which you have is the main task. Three cases dominate:

What it isHow to recognise it
IsoBuster disc-image segmentA companion .IBP or .IBQ file sits in the same folder
Generic split-file first partSiblings .001, .002; joining them reveals a header such as PK (ZIP), 7z or Rar!
Encrypted volume (TrueCrypt/VeraCrypt)High-entropy random-looking bytes with no header at all

The second case overlaps with the generic .001 convention, which owns the split-file meaning. Many splitters (HJSplit, 7-Zip) cut a large file into .000/.001/.002 chunks that you rejoin by putting them in one folder and opening the first part. The third case is rarer: an encrypted container occasionally saved with a numbered name, which will look like random bytes and refuse to open in any disc tool. Checking the file’s origin, and its first bytes, tells you which path to take.

Turning a .000 image into a usable ISO

The most useful thing to do with an IsoBuster .000 is to convert the managed image into a standard ISO, which modern Windows mounts natively and any tool can burn. Open the .IBP in IsoBuster and use its extract/save-as-ISO command; IsoBuster reassembles the segments and writes one .iso. If instead your .000 set turns out to be a split ISO rather than a managed image, you do not convert at all: you simply join the parts (with 7-Zip, or copy /b on Windows, or cat on macOS and Linux), and the joined result already is the .iso. For discs that carry audio or multiple tracks, a plain ISO cannot represent them, so IsoBuster or UltraISO can export a .bin plus a .cue track list instead.

Why a lone .000 usually cannot be used

Whatever the .000 turns out to be, completeness matters. An IsoBuster image needs its .IBP header and every numbered segment; a split archive needs every part with unbroken numbering. A single .000 on its own is just the first slice of something larger, and the missing bytes cannot be reconstructed, so it cannot be reassembled alone. If you have only the .000 and none of its siblings or the descriptor, the practical answer is that you need to obtain the rest of the set from wherever the file came from.

Is a .000 file safe, and safe to delete?

A .000 segment is passive data and cannot execute by itself, but caution applies to what it contains. A disc image can hold installers and executables, so scan anything you extract before running it. An unexpected .000 may actually be a split archive, which can carry malware once joined and extracted, or an encrypted volume. As for deleting: a .000 is safe to remove only if you no longer need the disc image it belongs to and still have the original disc or another backup; deleting one segment of a set makes the whole image unrecoverable. Download IsoBuster, UltraISO or PowerISO only from their official sites, and avoid generic “ISO opener” download portals that bundle adware.

Frequently asked questions

How do I open a .000 file?

If it came from IsoBuster, open the matching .IBP file in IsoBuster rather than the .000 itself; IsoBuster reassembles the segments into one image. If it is a split file (file.000, file.001, ...), put all the parts in one folder and open the .000 with 7-Zip to join them. Where the file came from tells you which case you are in.

Why won’t my .000 file open in IsoBuster?

Because it is probably not an IsoBuster image. The .000 extension is also the first part of a generic split file (open it in 7-Zip with the other parts present) and is sometimes a TrueCrypt or VeraCrypt encrypted volume (which looks like random bytes). Check the file’s source and look for a companion .IBP.

Is a .000 file the same as a .001 file?

They are the same idea, sequentially numbered segments of a larger file, just with different starting numbers. IsoBuster numbers its image data from .000, while many splitters start at .001. Either way, you join all the parts, in order, to rebuild the original. The .001 page covers the generic split-file case.

References