I recently got a new phone, a Samsung A21s. The problem i had was that Android File Transfer would not work with my Mac OS 10.13.6. I tried everything.
I then went to my Imac and AFT worked. I have tried three cables and two phones (my wife has the same phone and that would not connect either)
Going by that it it seemed to be my macbook that was the problem.
So, i wiped my macbook and reinstalled the OS, AFT worked!!, as i loaded the each piece of software i checked AFT and it worked ok.
What caused AFT NOT to work i have no idea but it works now.
That was my work around, drastic maybe but it worked. It probably took about three hours to get back to where i was before AFT stopped working.
I then went to my Imac and AFT worked. I have tried three cables and two phones (my wife has the same phone and that would not connect either)
Going by that it it seemed to be my macbook that was the problem.
So, i wiped my macbook and reinstalled the OS, AFT worked!!, as i loaded the each piece of software i checked AFT and it worked ok.
What caused AFT NOT to work i have no idea but it works now.
That was my work around, drastic maybe but it worked. It probably took about three hours to get back to where i was before AFT stopped working.