Launching tensorboard error - ImportError: cannot import name weakref
For those with the same problem I was able to fix it through the following:
1) find where your tensorflow lives pip show tensorflow and look at the location line, copy it.
2) For me it was cd /usr/local/lib/python2.7/site-packages/
3) cd tensorflow/python/lib
4) open tf_should_use.py
5) In your python editor replace line 28 from backports import weakref with import weakref and save the file.
With python 2.7 on a mac with tensorflow and running 
tensorboard --logdir= directory/wheremylog/fileis produces the following error ImportError: cannot import name weakref
I've seen several folks remedy the issue with pip install backports.weakref
 but that requirement is already satisfied for me. Requirement already satisfied: backports.weakref in /usr/local/lib/python2.7/site-packages

I am out of ideas and am really keen to get tensorboard working. 
Thanks