I'm using a Macbook Pro OS X Sierra, with Android File Transfer installed. When plugging in an Asus Zenfone 2, a popup shows with the message (minus the Initialize button):
However, this is followed immediately with another window listing the contents of said phone, with buttons for both Internal Storage and SD Card. Drag and Drop/Copy-Paste file transfers are possible as well (not my screenshot but very similar to mine):
Also, when checking System Information in About This Mac/Overview/System Report/USB, "Android" is visible under the USB Device Tree. Clicking this further shows additional data such as Product and Vendor IDs, etc. (image not mine but similar):
When in Terminal, typing "adb devices" will list the device's Vendor ID.
Long story short, the device is recognized except in Finder.
Any suggestions how to make the device appear in Finder's Sidebar, under Devices? Any help would greatly be appreciated. TIA!