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What is an M4B File?

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Question: What is an M4B File?

Did you find an M4B file on your computer and wonder what program should open it? Maybe someone emailed you an M4B file but you're not sure how to use it. Perhaps you tried to open the M4B file but Windows told you that it could not open it.

Before you can open an M4B file (assuming it's even a file format that's intended to be viewed or edited), you'll need to determine what kind of file the .M4B file extension refers to.

Answer: A file with the M4B file extension is an MPEG-4 Audio Book file.

Other types of files may also use the M4B file extension. If you know of any additional file formats that use the .M4B extension, please let me know so I can update this information.

How To Open an M4B File:

The easiest way to open an M4B file is to double-click on it and let your PC decide which default application should open the file. If no program opens the M4B file then you probably don't have an application installed that can view and/or edit M4B files.

Warning: Take great care when opening executable file formats received via email or downloaded from websites you're not familiar with. See my List of Executable File Extensions for a listing of file extensions to avoid and why.

M4B files can be opened with Windows Media Player but you may have to open Windows Media Player first and then open the M4B file manually since Windows may not recognize the M4B extension. Another option is to rename the extension from M4B to M4A, a nearly identical format that Windows does properly associate with Windows Media Player.

Other multi-format media players that natively support the very similar M4A format, like VLC, will also play M4B files.

Tip: An M4B audio book that your purchase (versus download for free from a site like LibriVox) is likely protected by DRM, meaning that it will only play using authorized computer software and devices. For example, most M4B based audio books that you purchase from the iTunes store are DRM protected and will play only in iTunes and devices authorized via iTunes.

If you know of any other program that can open or edit M4B files, or you know anything else useful about M4B files, please let me know so I can update this page.

If you find that an application on your PC does try to open the M4B file but it's the wrong application, or if you would rather have another installed program open M4B files, see How To Change the Default Program for a Specific File Extension for instructions on making that change in Windows.

How To Convert an M4B File:

There are two main ways to attempt to convert an M4B file to another file type:

The first option involving opening the M4B file in its native program is preferable because it's both easier and will probably result in a more accurate file conversion. Of course if you don't have a program that opens M4B files, a third-party file conversion tool (the second option) could be very useful.

Important: You cannot usually change a file extension (like the M4B file extension) to one that your computer recognizes and expect the newly renamed file to be usable. An actual file format conversion using one of the methods described above must take place in most cases. As I mentioned previously, however, try renaming the M4B file to M4A, a trick that is very often successful, at least for non-DRM protected M4B audio books.

Still Having Problems Opening or Using an M4B File?

See Get More Help for information about contacting me on social networks or via email, posting on tech support forums, and more. Let me know what kinds of problems you're having with opening or using the M4B file and I'll see what I can do to help.

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