The primary function of an email application is sending and receiving emails, but if you are unable to download attachments it becomes a huge problem as it leads to disruption of online communication. In Windows, the MS Outlook Saves the Emails in PST File Format and on Mac it saves the emails in OLM File Format. It is available for both Windows and Mac Operating Systems but has a separate file format for saving data. The MS Outlook is a very widely used email service by most businesses. Solution 4: Try a Professional Softwareįree Methods to Fix Mac Outlook 2016 Error.Solution 2: Download attachment using Office 365 Account.3 Solutions to fix Unable to Download Mac Outlook Attachments Error.Free Methods to Fix Mac Outlook 2016 Error.