This is only my case though, but trying everything else, this was the most simplest (i think)
When you get "error: more than one device and emulator" even though you know there is only one device that is connected to the PC
what you put in cmd is quite simple.
1. adb kill-server
2. adb start-server
3. adb "whatever you were trying to do"
That fixed my problem for good!
Doesn't matter if it's rooted or not!
Don't think this is the problem since my phone was NOT rooted, but adb push and pull all worked without rooting!
Just wanted to help those who might need this.
I apologize in advance if this is a re-post
ps this is my first forum