There is a known issue where this may happen, after you've made some changes in your scene that affects the number of lights. Could you please try to close the render window and start Enscape and try again if that happens?
We've fixed that and it'll be released with an upcoming hotfix in the next couple of weeks. In the meantime it will be available as a Preview version, which is expected to be released this week.
There're multiple possible causes for noise like that. Are you using any Enscape light sources at all in that scene, or are the lights only modeled with the visible emissive materials? That might be one issue - small emissive surfaces with high brightness tend to result in much more noise in path trace renderers in general.
Great, so thank that Enscape make a lot of effort on making this software better.
No, i put not only one enscape light to light the scene. My brightness of emissive is not very hight, i also increase the exposure to let the scene brighter but it still happen. Is there possible that my IES file caused this problem?