Files are disabled and cannot be imported in macbook

[sezeneren]

When tried to access to files (cpanel backup files within the cur folder) in macbook, the files are inaccessible. Macbook has show options button which opens up the option to chose the file format, which is by default is "email". With this option, the "all files" is selected but the files are still inaccessible, the open button is not enabled.
I can open the same files with the Thunderbird -> open saved messages, and the files are accessible and I can open the emails within Thunderbird, however cannot import them.