I’m trying to upload my database backup from a mac but it’s greyed out

Some versions of Mac OS appear to show the database file (ending in db.gz) as greyed-out when you try to upload it from the file selector. (This is apparently because the Mac doesn’t know what a db.gz file is).

If this happens to you, then open the Mac’s directory browser application, and drag-and-drop the file instead. If that doesn’t work, then drag-and-drop it more slowly!