Why can’t I import emails from Mac Mail to Outlook 2011 for Mac

Previously I exported the emails from mac mail, that created a file on my home screen that says "Gmail" and contains all the folders in .mbox format.

Now I am trying to import this folder in ourlook 2011 using the import wizard and when the choose folder option appears, the file which I need to choose is greyed out and i can select that file.

Please help me with this issue of importing the emails from apple mail to outlook 2011 for mac.

Helpful answers will be appreciated

Thanks