nT Colorations crashes after the regular performance (one design, coloring, export, close, and repeat).
The reason could be the usage of Graphic Card Settings in Photoshop that needs modifications or has to be disabled in Photoshop Preferences > Performance.
1. As first change the drawing mode in Advanced Settings from 'Advanced' to 'Basic' and restart Photoshop.
2. If this does not resolve the issue, disable the graphic processor and restart Photoshop.