python2.7 cannot be opened because of a problem

Solution 1:

Was fighting with this issue today, after I upgraded python using brew, the annoying pop up wouldn't let me work on my Mac! The only difference is that it was shouting for python3.4. After couple hours of digging I just decided to:

• remove all python3 whatsoever, the one installed by brew and the one installed manually from dmg.

• search for all remaining symlinks to python I've had on my development projects folder. After deactivating all the venv's and removing the symlinks the pop up was gone.

Then I found this post of jeremycade which explains the less aggressive approach.