File extension CWK is most commonly associated with a ClarisWorks document. Claris, the company behind ClarisWorks, was bought by Apple in 1998 and rebranded the suite as AppleWorks, which also used the CWK file format.
ClarisWorks is an integrated suite of office applications which was developed for use on the Macintosh and Windows platforms. ClarisWorks 1.0 first appeared on the Macintosh in 1991, with a Windows version released in 1993, and offered word processing, drawing, image editing, spreadsheet, database and terminal communication functionality. ClarisWorks used the CWK file extension, which could denote a document produced using any of these components.
Unlike other office suites, ClarisWorks was designed to integrate seamlessly, allowing the embedding of frames within other documents. This meant that drawings, spreadsheets or images could be embedded within a word processed document, for example. Claris, the company behind ClarisWorks, became part of Apple following release of version 5, and the software was subsequently rebranded as AppleWorks 5. Both AppleWorks 5 and AppleWorks 6, the last version to be released, maintained the proprietary CWK file format, though were able to export documents in other formats which were more widely supported, such as Microsoft's DOC or XLS formats. AppleWorks 6 also included support for presentations at the expense of the terminal communications functionality.
CWK files may contain anything from a word processed document or spreadsheet to a database or vector drawing. As CWK is a proprietary binary format, they cannot be inspected using a text editor and as such the only way to determine the contents of a file is to open it using ClarisWorks or AppleWorks depending on the version of the software it was originally created in.
CWK files can be properly opened using an appropriate version of either ClarisWorks or AppleWorks on either the Windows or Macintosh platform. However, AppleWorks was discontinued in 2007 and will no longer be sold or developed, rendering CWK as a legacy file format. CWK files can be opened using AppleWorks successor, iWork, though support is limited and formatting or embedded object data may be lost in the conversion process.
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