CPT File

What are CPT files and how to open them

Are you having problems opening a CPT file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your CPT files.

What is a CPT file?

CPT files have multiple uses, and Corel PHOTO-PAINT Bitmap Image is one of them. Read more about the other uses further down the page.

Corel PHOTO-PAINT Bitmap Image

Files that contain the .cpt file extension are most commonly associated with the Corel PHOTO-PAINT image editing application. Corel PHOTO-PAINT is a part of the CorelDraw suite of software applications.

The CPT files that are used by this application store bitmap images that have been created with the application. These files are bitmap pictures or graphics files that contain editable layers.

The PHOTO-PAINT software can be used to touch up photographs and then export the images into more popular image formats such as the PNG, BMP, and JPG file formats.

How to open CPT files

We have identified one CPT opener that is compatible with this specific type of CPT file.

Programs that open Corel PHOTO-PAINT Bitmap Image files

Last updated: September 18, 2026

All known file formats using extension .CPT

While Corel PHOTO-PAINT Bitmap Image is a popular type of CPT-file, we know of 4 different uses of the .CPT file extension. Different software may use files with the same extension for different types of data.

Compact Pro Compressed Archive

Compact Pro Compressed Archive files are archives created by the Compact Pro utility on classic Macintosh systems. They bundle multiple files and compress them to save disk space or make it easier to transmit or store many files together. These archives were often used under Mac OS in the 1990s and can also be self-extracting so that the compressed files can be decompressed without needing the original archiver program.

The Compact Pro program, developed by Bill Goodman of Cyclos, writes these archives. It takes file data (including embedded resource forks and Finder metadata) and compresses it into a binary archive format. Users or other utilities later read or expand these archives to retrieve the original files, optionally converting formats like BinHex-encoded data back into native Mac format.

Files in this archive format begin with specific byte patterns: the first byte is 0x01, followed by another 0x01 at offset 1. At offset 4 there is a zero byte. After these initial signature bytes, larger-than-one-byte fields like multi-byte size or offset values are stored in big-endian order, consistent with Mac conventions.

While we have not verified the apps ourselves yet, our users have suggested ten different CPT openers which you will find listed below.

DTS Compact Audio File

DTS Compact Audio File is a stream of audio encoded using the DTS Digital Surround codec, stored in a compact bitstream format without padding. It is created by systems that perform DTS audio encoding, especially when the compact variant is selected. Such files are used in professional audio and DVD-authoring workflows to hold the core DTS payload with minimal overhead. The format omits padding but retains timecode or start-time markers so that precise synchronization with video or other audio tracks is possible. It uses big-endian (Motorola) byte order. The data includes DTS frame headers and encoded audio frames.

The DTS encoder marks these files as compact by removing trailing zero padding and any extended "padded" structure. A comparable alternative in many encoding tools is a padded format, which includes zeros so that all frames reach fixed size; compact format avoids that and typically produces smaller files. Some encoders also offer a WAV-style header or timecode only in the compact version.

Bytes at the very start of the file match the DTS sync signature 7FFE8001FC3C7DC277000D3B8009EF7BDEF7BDEF0000FFF6DB6DB6FFFFFFFFFFFFFFFF, followed by fields including timecode or start-time markers. This signature allows tools to detect DTS Compact Audio files.

Mac Compact Pro Archive File

This is a compressed archive format created by Compact Pro, a shareware archiving utility for Classic Mac OS (pre-Mac OS X). It bundles one or more files and folders, preserving Macintosh metadata such as resource forks and Finder attributes. Users typically encounter .CPT archives when backing up files, transferring software, or sharing collections of Mac files from the early 1990s.

The Compact Pro application is the original tool that writes .CPT files. It offers compression to reduce file size, optional encryption, the ability to split large archives (for storage on floppy disks), and support for self-extracting versions. Extracting or restoring the archive requires Compact Pro itself or utilities like StuffIt Expander that are capable of handling Classic Mac archive formats.

Inside the file there are internal signatures that identify it as Compact Pro archive. One pattern is that the first byte at offset 0 is 0x00. It also contains the ASCII strings "CPCT" and "PACT" somewhere in the file, which serve as markers for verifying the format.

Programs associated: Stuffit Expander - current decompression support by vendor. Known signature patterns: Byte 0x00 at offset 0; ASCII "CPCT" and "PACT" embedded.

CPT opener for Windows

We have identified one CPT opener that is compatible with this specific type of CPT file.

Various apps that use files with this extension

These apps are known to open certain types of CPT files. Remember, different programs may use CPT files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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