What is the TOAST file format?
.toast is a macOS-exclusive proprietary disc image format produced by Roxio Toast Titanium, a Mac-only optical disc burning and image management application. The .toast extension was introduced with Toast 5.1 (2002). Toast is currently published by Corel Corporation, which acquired Roxio; the current release is Toast 20 Titanium (2024).
A .toast file is a sector-by-sector binary image of an optical disc stored in ISO 9660 format. Some files include an Apple Partition Map header (magic bytes 45 52 02 00); many also carry the internal text string TOAST ISO 9660 BUILDER COPYRIGHT (C) 1997 ADAPTEC, INC. near the file start. Because most .toast files are structurally valid ISO 9660 images, renaming the file to .iso and mounting it with macOS Disk Utility works in the majority of cases. Audio CD images and HFS+-only volumes may not convert as cleanly.
.toast images have no built-in checksum; integrity depends on the ISO 9660 volume structure. The format is macOS-only - Toast Titanium has never been available for Windows. For universal disc archiving, .toast has largely been replaced by .DMG for macOS software distributions and .iso for cross-platform use.
Security & safety
RISK: LOW.toast files are passive disc images - they contain no executable code beyond whatever was on the original disc. Risk depends entirely on the disc contents (installers, etc.). Be cautious with .toast files downloaded from untrusted sources, as they may contain autorun scripts; open in Toast or extract with a tool before running any executable.
Format details
in a nutshellPrograms that open TOAST files
Windows2 apps
macOS3 apps
Roxio Toast 20 Titanium
Paid Open the .toast file directly in Toast to mount, burn, or convert it. Current version as of 2026 is Toast 20 Titanium (requires macOS 10.14+).
macOS Disk Utility / Finder (rename trick)
Built-in Rename the file from .toast to .iso, then double-click in Finder to mount as a virtual disc - works for standard data disc images.
AnyBurn (via Wine/Crossover on Mac, or Windows)
Free On Windows via CrossOver or a Windows PC: convert .toast to .iso. Primarily a Windows tool. Technical details
deep spec| Encoding | Binary; metadata uses big-endian byte order (ISO 9660 / Apple convention); data area is endian-agnostic |
| Base format | ISO 9660 sector-by-sector disc image; may include Apple Partition Map header (magic bytes `45 52 02 00`) in early files |
| Internal text marker | Many files contain the string `TOAST ISO 9660 BUILDER COPYRIGHT (C) 1997 ADAPTEC, INC.` near the file start |
| Platform | macOS only; Roxio Toast Titanium has never been available for Windows |
| Supported disc types | CD (up to 700 MB), DVD single-layer (4.7 GB), DVD dual-layer (8.5 GB), and Blu-ray images |
| ISO compatibility | Most `.toast` files are valid ISO 9660 images; renaming to `.iso` works for standard data discs in the majority of cases |
| Compression | None (raw sector-by-sector image) |
| Checksum | None built-in; integrity relies on ISO 9660 volume structure verification |
| HFS+ support | Some `.toast` files include HFS+ (Mac OS Extended) metadata for classic Mac software; these may not mount cleanly when renamed to `.iso` |
| Multisession | Metadata can optionally record multisession CD/DVD information |
| File extension era | `.toast` extension introduced with Toast 5.1 (2002); earlier Toast versions used proprietary images without this extension |
| Current publisher | Corel Corporation (acquired Roxio; current release: Toast 20 Titanium, 2024) |
| Released | 2002 (Toast 5.1 introduced .toast extension) |
| Latest version | Toast 20 Titanium (2024); format itself has not changed significantly since Toast 5 |
| Specification | www.roxio.com |
TOAST conversions
Community Q&A
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