Can't copy files from Windows to Android? I have a Galaxy 5s with a 32GB external card, which I connect to my Windows 7 x64 PC with a USB 2.0 cable.   I can copy files from my phone to the PC all day long with no problems.  Copying files to the phone from the PC is virtually impossible, however.  

I can open the phone's card in Windows Explorer, and look at all the files.   But trying to copy anything onto the card hangs explorer.  Right now I'm trying to copy a 42MB MP3 file from my PC to the phone - it's telling me "27 minutes to go" and it's already taken half an hour.

I checked this question from 2013 which seems like the same problem, but basically the answers were "you can't get there from here."   Was wondering if anyone had a solution for this.
As a fast solution I would recommend FTPServer as mentioned above.I had a similar problem and that was the drivers from Samsung.Maybe a little driver upgrade would solve your problem . Google USB Driver