Conda build fails on MacOS

[lenhsherr]

The conda build rdkit command fails with this error:

Exceeded max retries, giving upLock error:
LOCKERROR: It looks like conda is already doing something.
The lock [u'/Users/admin/anaconda2/pkgs/fontconfig-2.11.1-py27_3.tar.bz2.pid48308.conda_lock'] was found. Wait for it to finish before continuing.
If you are sure that conda is not running, remove it and try again.
You can also use: $ conda clean --lock