Cura with Pronterface UI stops printing
A problem I have come across when using Pronterface is that the operating system starves the resources of the program if the program's window is not in the front.

If I, for instance, started a print, then started browsing the web, it would sometimes suddenly stop. When bringing Pronterface back to the front, it would take a few seconds, and then continue (if I remember correctly).

On OS X - which I am using - I believe this is called app nap, while a similar mechanism exist for Windows. I ended up printing form an SD card myself after this, but you might want to try manually setting the resource priority for Pronterface in your OS.

In Windows, you could trying to increase the resource allocation for Pronterface by going to Task Manager -&gt; Details -&gt; Right click the Pronterface process -&gt; Set Priority. I would be careful to set it too high, since you are basically allowing the program more juice to potentially do something wrong.

In OS X you could try to disable app nap for Pronterface.