Issue Summary

When you try to export the board as CSV or JSON file you get a pop-up window to let another application handle blob. Even you if allow it nothing happens. There is no other application to handle it. This problem exists on both Mac and Windows client. 

Steps to Reproduce

1. Open desktop app
2. Go to any Premium/Enterprise Workspace
3. Open a board
4. Go to settings and try to export the board

Expected Results

The CSV or JSON file with board contents gets downloaded

Actual Results

You get a pop-up message asking to allow another application handle the blob. Allowing it doesn't help, the file is still not downloaded.

Workaround

You can export the board via browser version of Trello.