COP File

What are COP files and how to open them

Are you having problems opening a COP 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 COP files.

What is a COP file?

COP files have multiple uses, and Capture One Proxy is one of them. Read more about the other uses further down the page.

Capture One Proxy

Capture One Proxy files store preview image data generated by Phase One's Capture One software to represent raw or source images at a smaller size for fast display. They allow Capture One to show image previews in sessions or catalogs without repeatedly rendering the full-resolution raw file. In effect, they act like editable proxies: image viewing, zooming (up to the preview's maximum size), and certain metadata changes work via these files, though full processing or export to final output formats generally uses the original raw plus adjustment settings.

These files are created automatically by Capture One whenever the source image is viewed or browsed in a session. They are stored in a Cache - specifically the Proxies cache - alongside other sidecar files like thumbnails (.cot) and mask (.cof) files. Because Capture One never modifies the original raw file, all preview and adjustment information is saved in these proxy or other sidecar files. If originals are missing, the proxy files serve limited display and export (QuickProof) roles, but cannot replicate full raw fidelity.

Files begin with a specific byte signature at offset 0 (a sequence including 47CA06001B), and contain recognizable metadata-style strings such as IFD0, IFD1, JFIF, XMLNS, XMPMETA, LEVEL'0 through LEVEL'7, and others. These internal markers indicate embedded metadata and structured image preview content and help distinguish Capture One Proxy files from other uses of the same extension.

How to open COP files

Important: Different programs may use files with the COP file extension for different purposes, so unless you are sure which format your COP file is, you may need to try a few different programs.

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

Last updated: September 2, 2026

All known file formats using extension .COP

While Capture One Proxy is a popular type of COP-file, we know of 2 different uses of the .COP file extension. Different software may use files with the same extension for different types of data.

E-Tracker Chiptune

E-Tracker Chiptune files store music created using E-Tracker on the SAM Coupé home computer. This format captures the compositions made in E-Tracker, a tracker program comparable to SoundTracker, designed for making multi-channel chiptune music using the SAM Coupé's built-in Philips SAA1099 sound chip. Songs consist of patterns of notes, instruments, effects, tune and author metadata, and are played back by the E-Tracker player code.

E-Tracker was released in 1992 by Fred Publishing for the SAM Coupé, first as version 1.2 and later as version 2.3. The newer version increased the number of patterns from 32 to 256 and introduced variable-length pattern storage rather than fixed allocation. Tune and author fields were renamed as part of that update. Compositions saved in this format are edited via E-Tracker, then played back by the SAM Coupé through its PSG-style sound chip which supports six audio channels and stereo control.

Files in the format begin with a signature at byte offset 10: the ASCII string "ETracker(C)BYESI". Other extensions used historically include ET, ETC, and just T. Same extension COP is used uniquely for this format when distinguished by that signature.

Various apps that use files with this extension

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

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about COP file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.