Many Apple MacOS users have been complaining for years about a problem with previewing files using the QuickLook component. The component is used to generate a preview without necessarily opening the file and normally its behaviour is normal and useful, but with EML files there can be problems. Below I explain how I solved the problem.
The problem
When exporting one or more messages from mail clients such as Mozilla Thunderbird or emClient, the EML file is correctly saved but not correctly displayed by the QuickLook component. When asked to preview, the component correctly displays the headers (sender, recipient, subject) but not the message body.
Why does this happen
Opening the EML file with a text editor reveals that it most likely contains the CR line terminator. In my case, for example, the EML files exported by Thunderbird were CRLF while the files exported by Apple Mail were only LF.
Solving the problem
Inside Thunderbird use the ImportExportTools NG extension and be sure to remove the checkbox “Remove CR from line endings for eml message exports”. This command should solve the problem. Perform a message export to test the actual resolution.
