Files with msf extension contain mail summary data from Mozilla Thunderbird, an e-mail client for Windows, Mac and Linux. 

There are 6 other file types using
the MSF file extension!

empty icon.msf - Epson data

empty icon.msf - Quanta MSF chemical modeller input file

empty icon.msf - Multiple sequence data

msf icon.msf - Miranda IM skin settings file

empty icon.msf - Sony recorder data

empty icon.msf - Altera Mask settings

MSF file extension - Mozilla Thunderbird mail summary

What is msf file? How to open msf files?

File type specification:

Email related data file type icon Email related data file type

File extension msf is associated with Mozila Thunderbird. Thunderbird's mail files are in the standard plain text "mbox" format, which almost all mail programs can use or import.

Many proprietary mail programs have a function to import from Eudora, which also uses the "mbox" format; this function should read your Mozilla mail files properly.

Your mail files are inside your profile (see the Profile Folder), in the Mail and (if you use IMAP) ImapMail folders.

Each mail folder (Inbox, Sent, etc.) is stored as two files — one with no extension (e.g. INBOX), which is the mail file itself (in "mbox" format), and one with an msf file extension (e.g. INBOX.msf), which is the index (Mail Summary File) to the mail file. Tell the other program to import mail from the file with no extension.

Updated: November 21, 2023

The default software associated to open msf file:

Mozilla Thunderbird icon

Mozilla Corporation logoMozilla Thunderbird  Microsoft Windows software

Company or developer:
Mozilla Corporation

Mozilla Thunderbird is easy to use e-mail client with spam protection and e-mail managing features.

Help how to open:

The *.msf file is used by Thunderbird for internal purposes.

How to convert:

It doesn't seem very likely that conversion of any kind is possible for this type of .msf files.

File identification strings:

HEX code: 2F 2F 20 3C 21 2D 2D 20 3C 6D 64 62 3A 6D 6F 72 6B
ASCII code: // !-- mdb:mork:z

List of software applications associated to the .msf file extension

Recommended software programs are sorted by OS platform (Windows, macOS, Linux, iOS, Android etc.)
and possible program actions that can be done with the file: like open msf file, edit msf file, convert msf file, view msf file, play msf file etc. (if exist software for corresponding action in's database).

Click on the tab below to simply browse between the application actions, to quickly get a list of recommended software, which is able to perform the specified software action, such as opening, editing or converting msf files.

Programs that can create msf file - Mozilla Thunderbird mail summary

Programs supporting the exension msf on the main platforms Windows, Mac, Linux or mobile. Click on the link to get more information about listed programs for create msf file action.

Microsoft Windows:

Apple macOS / Mac OS X:

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