So Enlighten can update lighting in real time, you need to run the Enlighten Precompute to create the Enlighten data for the level. 

 The precompute creates optimized runtime data containing information about static actors in your level (actors in your level that have a fixed shape and position).

1. From the Build menu, select Enlighten Precompute.
   
   The Enlighten precompute starts. GeoPrecompMonitor opens, showing the Enlighten precompute progress.
   
   A notification shows that the Enlighten precompute is running.
   
   The precompute may take a few minutes the first time you run it. You can still use the editor while the precompute runs. 

2. When the precompute is finished, click Apply Now, or wait for it to apply automatically.
   

   The Enlighten precompute requires a valid Enlighten license. If you see an error message about your Enlighten license, notify the person who provided your Enlighten UE4 build.

   Now you've run the Enlighten precompute, the lighting will update instantly when you add or move light sources in the next steps.

Next

• 3. Turn emissive materials into light sources