.MIM File Extension

Encoded file used by email programs; contains 8-bit data or other characters besides the US ASCII character set; used to support 8-bit content, such as file attachments, instead of standard 7-bit messages that are normally sent over email; typically include the MIME version, the content type, and the encoding method.

MIM files may either appear as part of an email message, or they may be included as a separate attachment. They are often automatically decoded by email programs, but can also be decoded using a separate decoding utility.