About a million years ago (2011 to be specific) Google changed the default USB transfer mode from mass storage to MTP in Android. By now, you'll be hard pressed to find a phone that hasn't switched over, and most of us are used to using MTP — that's Media Transfer Protocol — to move files around while your phone is connected to your computer. Way back when Google first adopted MTP they also introduced an OS X app called Android File Transfer. MTP wasn't supported natively on a Mac (it's a standard, but based on some old Windows Media framework files) and they knew that people using Apple computers would need an easy way to transfer files. Then they stopped working on it.
There are good reasons to use MTP. It lets your phone and your computer access the storage at the same time, has safeguards in place so you can't mess with necessary system files that might be stored in your user storage, and allows the people who make our phones to use a different (some say better) format for internal storage. Naturally, there was some resistance when Google first made the move, but by now most of us are used to it and don't give it a second thought. Unless you use a Mac and AFT, that is.
If you download the very latest version of AFT from Google, you get an app that hasn't been updated since October 2012. I get it — some utilities just work and don't need to be updated. AFT is not one of them.
I'm sure the Android team has been working on MTP in Android versions since Honeycomb. Things that are designed to appear easy to the user are usually very complicated under the hood. It's likely that some tweaks could be made to make the AFT app perform better or transfer faster or do something else that's better. Three and a half years is a long time, and something has to be better. Maybe.
If nothing else, an overhaul to the UI is in order. How about the ability to plugin to Finder? Or at least a dialog box that has kept up with the rest of OS X. Looking like an Excel '98 doc is kind of retro and cool, but I'd rather have a standard Apple dialog like everything else has.
I could live with the AFT app not being updated since October 2013 if not for one thing — Marshmallow doesn't choose MTP by default when you plug a phone into a computer.
Google has the geeky way of transferring files sorted out pretty well. Install the SDK, turn on USB debugging, fire up your terminal and do everything you can do. I usually just do things this way, but I'm not a normal user. I like the command line, and the easy access it gives me to all sorts of things when I'm using a computer. Regular folks — the billion plus who are using Android — just want to plug a phone in and drag and drop like everything else does. With a Marshmallow phone and a Mac, that doesn't happen.
When you plug your phone in, the AFT app on your Mac starts up, but your phone isn't ready. All you get is an error in the middle of your desktop. Most of the time, you can change the USB mode to MTP on your phone, close the error dialog and AFT will start back up normally. But not every time. I've even had to reboot my computer to get it working a time or two. And I'm not alone. Our company Slack channel has more than a few instances of the words AFT and **** in the same sentence.
I'm not asking for much. Just fix the broken parts. We'll all thank you for it.