I'm having trouble with the show() function not blocking. I've taken over a python application from someone that left and I seem to remembering this worked on his (IT reclaimed) PC. Here's the code ... import matplotlib.pyplot as plt plt.title("Molding X Error") plt.xlabel("X") plt.ylabel("X Error") plt.plot( ... details that work and not the problem ... ) plt.show(block=True) plt.title("Molding Y Error") plt.xlabel("Y") plt.ylabel("Y Error") plt.plot( ... details that work and not the problem ... ) plt.show(block=True) On the other guys PC, the first show() would display appropriately. After dismissing the first, the second would display. I run it, and it not only doesn't stop on the first show(), it combines data from both the first and second with the title and labels from the second. I step through with the debugger, and the first does show, but stepping to the second the same result is seen. Windows 7 Pro 64-bit. Python2.7.10, Anaconda 2.3.0 which contains (apparently) matplotlib1.4.3 Note: I did read through "(python) matplotlib pyplot show() .. blocking or not?" where it was from 2011 and was referring to matplotlib1.0.1 as a solution. Continue reading...