I printed a part but it is not complete. What could have cause this to happen, and how can I avoid it in the future? Thanks!
I am using grey resin from Formlabs. The layer thickness I used is 0.1mm despite what it says at the bottom of the screenshot. I used auto-orient and auto-generated supports in PreForm. 
This “incomplete” part failure is generally indicative of the model being under-supported. I would recommend trying a different orientation, or adding some supports in the trouble area. Sometimes models need some tweaking before the printing “sweet spot” is found.
Let us know if you keep having issues and we can take a look at the model file.
If your resin tank has some age on it that makes pealing harder, which can make delicate layers break, which is what you are seeing. The orientation you chose is very nice overall, but could be optimized for the hole by getting more model instead of a support under it. You could probably just add more supports to the failed area too.
Thanks for the help, but the same file has been printing fine lately (I need to make multiple copies of it). Don’t know what caused the initial defect, but it seemed to correct itself without intervention.