Mail drop not working
So i wanted to send a 600MB file via mail drop, but when I dragged the file onto the mail window and hit send, instead of the window asking me if I wanted to send it via mail drop, it just started sending it. Now I have a slow connection and don't want to spend the next 90 minutes uploading something that cannot be downloaded, never mind clogging up my internet connection.
So can anyone tell me how to ensure that mail drop actually works?
Incidentally, in trashing the uploading file in Mail's Outbox to stop it, I can see the upload still continues as my network stats show full upload speed. Had to restart. Seems very buggy to me.
MacBook Air, OS X Yosemite (10.10), 2.0 GHz i7, 8GB, 256GB SSD