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What are UNKNOWN files and how to open them

Are you having problems opening an UNKNOWN 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 UNKNOWN files.

What is an UNKNOWN file?

The .unknown file extension is often used by some data recovery tools for flagging files that have not been completely recovered. This UNKNOWN file format may also be used by a few data recovery tools for flagging files that have been corrupted beyond repair. These .unknown files may not work properly, even when opened using an application that has support for its original file format.The UNKNOWN file format may also be used by certain download management programs and P2P (peer to peer) file sharing tools. Files that have not been completely downloaded may be appended by these applications with the .unknown file extension. These UNKNOWN files may be converted by these download management and P2P applications into its original format as soon as the download has been successfully completed.It's best to leave these .unknown files alone, especially if the file is sent via email from an unknown source. Certain Web browsers may also flag incomplete download items as UNKNOWN files during the download process.

How to open UNKNOWN files

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

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Last updated: December 4, 2010

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