CKO file format description

Many people often share .cko files without providing instructions on how to use them. This can make it difficult for users to determine which program is compatible for editing, converting, or printing .cko files. To address this issue, we have created this page to offer assistance and guidance on handling .cko files. We provide information on compatible software, editing instructions and conversion options to help users effectively interact with .cko files.

Our aim is to simplify the process and promote seamless use of the .cko file format.

2 filename extension(s) found in our database.

.cko - ChessBase Key Openings

The CKO game data files are related to ChessBase. The CKO file is a ChessBase Key Openings. ChessBase is a personal, stand-alone chess database.

Game Data files
- / -
ChessBase Key Openings related extensions:
ChessBase Annotations
ChessBase Search Booster
ChessBase Commentators Index
ChessBase Hash File of Doubles Data
ChessBase Team Index
ChessBase Old Game Database

.cko - Kokogut C Output File

The CKO development files are related to Kokogut. The CKO file is a Kokogut C Output File. Kokogut is an implementation of Kogut in Kogut itself. It translates Kogut source into C source, which is then compiled using a C compiler to produce an excecutable. Kogut is an experimental programming language which supports impurely functional programming and a non-traditional flavor of object-oriented programming.

Development files
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Kokogut C Output File related extensions:
Kokogut Module Interface File
Kokogut Compiler Options File

Naturally, other applications may also use the .cko file extension. Even harmful programs can create .cko files. Be especially cautious with .cko files coming from an unknown source!

Can't open a .cko file?

When you double-click a file to open it, Windows examines the filename extension. If Windows recognizes the filename extension, it opens the file in the program that is associated with that filename extension. When Windows does not recognize a filename extension, you receive the following message:

Windows can't open this file:


To open this file, Windows needs to know what program you want to use to open it. Windows can go online to look it up automatically, or you can manually select one from a list of programs that are installed on your computer.

To avoid this error, you need to set the file association correctly.

The .cko file extension is often given incorrectly!

Based on searches conducted on our site in the past year, we have compiled a list of the most common misspellings. These frequent misspellings can cause confusion and hinder search accuracy. By providing this list, we aim to assist users in finding the correct information more easily and improving their overall search experience on our site.

These misspellings were the most common in the past year:

ck, cki, ckl, ckp, clo, cmo, co, cok, coo, cuo, dko, kco, ko, sko

Is it possible that the filename extension is misspelled?

There is a possibility that the .cko filename extension is misspelled. To assist users in identifying potential errors, we provide a list of similar file extensions in our database.

Filename extensions similar to .cko:

DISA STIG Checklist
Spanish Whiz Audio Data
Cloe Raytracer Image
Sage Accounting Executable
Autodesk AutoCAD Bounding Coordinates Cookie
Cult3D Object

Operating systems

At, we strive to provide a seamless user experience by ensuring compatibility with a wide range of operating systems. The following is a comprehensive list of the operating systems currently supported by

Windows XP/Vista, Windows 7/8/10, Windows 11, CentOS, Debian GNU/Linux, Ubuntu Linux, FreeBSD, macOS, Mac OS X, iOS, Android

If you find the information on this page useful, please feel free to link to this page.

If you have useful information about the .cko file format, then write to us! >> CKO file