For context this is ArcGIS 10.4.1 for Desktop using arcpy python 2.7 module.
So I have been working all day messing around with arcpy to modify some shapefiles I have with no issues at all. About an hour ago, I ran the same script as I had previously been running, but this time instead of ~20 seconds to import arcpy, it wouldn't even import after 30+ minutes. I've tried restarting my IDE (PyCharm) and debugging the import code.
What I found is that at the line below, the import hangs and nothing happens after this line is reached.
envset = (set(env for env in self._gp.listEnvironments()))
In the _base.py file.
I'm not sure if this is an issue on ESRI's side with validation of my license, but this problem has persisted for over an hour so far for what seems like no reason. I made absolutely no changes to my development environment and this is the first issue with importing since I got it to work about a month ago.
Just curious, any chance you upgrade to Pro 2.1.1, or hat you are using a borrowed/offline license (for desktop or pro)? Long shot, but I've seen several issues with import arcpy suddenly being slow. Seems like one of those to items might be involved. I have a support ticket for mine. My notes are found arcpy import is really slow (2+ minutes!!!) in the comments.