What is in the MB files?

All of the information required to represent a Mathematica® notebook (apart from platform-specific bitmap graphics) is stored as plain ASCII text. In the Windows and Unix versions of Mathematica, this plain text representation is stored in a file with an MA extension. This ASCII representation is platform independent, allowing you to share notebooks with Mathematica users on different computer platforms. It can also be easily transmitted via email.

Opening and interpreting the MA file can be time consuming. For this reason, a binary representation of the notebook is also created and stored in the MB file. It is much faster to open, among other advantages, and it stores the bitmap rendering of Mathematica PostScript graphics so they do not have to be rerendered. It also stores platform-specific bitmap graphics that will be lost if you discard the MB file.

The binary information stored in the MB file is somewhat more vulnerable to corruption than the plain text stored in the MA file. If you experience problems opening Mathematica notebooks, then discarding the binary file is often a good solution.

In the Macintosh version of Mathematica, the binary information is stored in the resource fork. For more information, please see the FAQ “How do I ignore/remove the resource fork from a Macintosh notebook?”.

Most of the time there should be no need to discard the MB files, but you will rarely lose important information by doing so. It will, however, take longer to open notebooks if you have discarded the MB file.

Download this FAQ as a Mathematica 5.2 Notebook

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