What is .MAILHOST file?
Stores preferences for the e-mail server used by MSN; installed with MSN software and required for MSN to check and send e-mail; typically named "MSN#.mailhost."
If the Mailhost file is corrupt or missing, the MSN software may display a "Mailhost File" error. To recover the Mailhost file, first select "Run..." from the Mac Start menu. Then type the following in the text box:
This should restore the Mailhost file and allow MSN to communicate with the mail server again.
Also see the related .DOWNLOADHOST entry.
Recommended Software Programs to open .MAILHOST file