Mail summary files contain email header data such as the date, time and sender. MSF files are primarily used by the email client Thunderbird, which uses these files, along with data contained in DAT and MAB files, to store email account information on your computer for cache or backup purposes. Opening the MSF file loads your email inbox in the state it was in at the time Thunderbird created the file, which is helpful for recovering a corrupted or otherwise inaccessible inbox.
Download Mozilla Thunderbird and follow the on-screen prompts to install it.
Right-click the MSF file and select "Open With" from the menu.
Click the "Mozilla Thunderbird" icon. If you do not see the Thunderbird icon, click “Look for an App on this PC” and find it under “C: | Program Files | Mozilla Thunderbird.” The program will launch and show the inbox.
Download Mozilla Thunderbird and follow the on-screen prompts to install it.
Right-click the MSF file and select "Open With" from the menu.
Click the "Mozilla Thunderbird" icon. If you do not see the Thunderbird icon, click “Look for an App on this PC” and find it under “C: | Program Files | Mozilla Thunderbird.” The program will launch and show the inbox.