.OLK14MSGSOURCE File Extension

Data file created by Outlook for Mac, an email program first released with the Office 2011 suite; contains all email source data for a message referenced in an .OLK14MESSAGE file; loaded when viewing a specific email message.

While OLK14MSGSOURCE files store the email message content, OLK14MESSAGE files only store header information. When browsing email message lists, the data in OLK14MESSAGE files is loaded, and when focusing on a specific email message, the data in an OLK14MSGSOURCE file is loaded. This allows the software to operate more efficiently.