MSF file icon

MSF File Extension

Mail Summary Format

What is MSF file?

MSF file format is used by many mail user agents (email client applications) such as Mozilla Thunderbird. The file, however, doesn’t store email message body , only sent or received message index, i.e. the message header and summary of the contents.

How does MSF format work?

MSF index file is created along with second file, MBOX, which is used for different tasks. Each email folder (Inbox , Sent, Drafts, etc.) stores content in two type of files :

  1. MBOX file – stored without file extension - holds the actual email message.
  2. MSF file – stored with MSF extension - holds the index file of given email message.

The idea behind MSF files

MSF are generated for the purpose of importing messages using other applications directly form MBOX folder. MSF format is considered the current standard, and is supported by many popular email clients.

Programs which support MSF file extension

The following list contains programs grouped by 3 operating systems that support MSF files. Files with MSF extension, just like any other file formats, can be found on any operating system. The files in question may be transferred to other devices, be it mobile or stationary, yet not all systems may be capable of properly handling such files.

Updated: 12/27/2019

How to open file with MSF extension?

Being unable to open files with MSF extension can be have various origins. On the bright side, the most encountered issues pertaining to Mail Summary Format files aren’t complex. In most cases they can be addressed swiftly and effectively without assistance from a specialist. The following is a list of guidelines that will help you identify and solve file-related problems.

Step 1. Install Mozilla SeaMonkey software

Install software to open MSF file Problems with opening and working with MSF files are most probably having to do with no proper software compatible with MSF files being present on your machine. The most obvious solution is to download and install Mozilla SeaMonkey or one to the listed programs: Mozilla Thunderbird, Netscape Mail. On the top of the page a list that contains all programs grouped based on operating systems supported can be found. If you want to download Mozilla SeaMonkey installer in the most secured manner, we suggest you visit website and download from their official repositories.

Step 2. Check the version of Mozilla SeaMonkey and update if needed

Update software that support file extension MSFIf you already have Mozilla SeaMonkey installed on your systems and MSF files are still not opened properly, check if you have the latest version of the software. Software developers may implement support for more modern file formats in updated versions of their products. If you have an older version of Mozilla SeaMonkey installed, it may not support MSF format. The latest version of Mozilla SeaMonkey should support all file formats that where compatible with older versions of the software.

Step 3. Set the default application to open MSF files to Mozilla SeaMonkey

If you have the latest version of Mozilla SeaMonkey installed and the problem persists, select it as the default program to be used to manage MSF on your device. The method is quite simple and varies little across operating systems.

Associate software with MSF file on Windows

Change the default application in Windows

  • Right-click the MSF file and choose Open with option
  • Next, select the Choose another app option and then using More apps open the list of available applications
  • Finally select Look for another app on this PC, point to the folder where Mozilla SeaMonkey is installed, check the Always use this app to open MSF files box and conform your selection by clicking OK button
Associate software with MSF file on Mac

Change the default application in Mac OS

  • From the drop-down menu, accessed by clicking the file with MSF extension, select Information
  • Find the Open with option – click the title if its hidden
  • Select Mozilla SeaMonkey and click Change for all...
  • If you followed the previous steps a message should appear: This change will be applied to all files with MSF extension. Next, click the Continue button to finalize the process.

Step 4. Check the MSF for errors

If you followed the instructions form the previous steps yet the issue is still not solved, you should verify the MSF file in question. Problems with opening the file may arise due to various reasons.

Check MSF file for viruses
1. Check the MSF file for viruses or malware

If the MSF is indeed infected, it is possible that the malware is blocking it from opening. Immediately scan the file using an antivirus tool or scan the whole system to ensure the whole system is safe. If the MSF file is indeed infected follow the instructions below.

2. Verify that the MSF file’s structure is intact

Did you receive the MSF file in question from a different person? Ask him/her to send it one more time. It is possible that the file has not been properly copied to a data storage and is incomplete and therefore cannot be opened. If the MSF file has been downloaded from the internet only partially, try to redownload it.

3. Check if the user that you are logged as has administrative privileges.

Some files require elevated access rights to open them. Switch to an account that has required privileges and try opening the Mail Summary Format file again.

4. Make sure that the system has sufficient resources to run Mozilla SeaMonkey

If the system is under havy load, it may not be able to handle the program that you use to open files with MSF extension. In this case close the other applications.

5. Check if you have the latest updates to the operating system and drivers

Regularly updated system, drivers, and programs keep your computer secure. This may also prevent problems with Mail Summary Format files. It may be the case that the MSF files work properly with updated software that addresses some system bugs.

Do you want to help?

If you have additional information about the MSF file, we will be grateful if you share it with our users. To do this, use the form here and send us your information on MSF file.

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