Delete old lightmaps from umap?

does anybody know a way to delete old lightmaps from the world / map file?
Each time I rebuild my light the lightmap count in the world settings increases and the umap file grows and grows…



Now I was able to delete the old lightmaps.
The solution mentioned here didn’t work for me (with 4.13) in the first step:
I had also to restart UE to get rid off the lightmaps.
So for anyone searching how to delete:

  1. Set “Force No Precomputed Lighting”
  2. Build Lighting
  3. Restart UE

Yep, that’s how it’s done

Hi ! it’s easy to delete the light information… Every map has a "Build Data’ or Map Build Data Registery and you can find it in a the parent of you map folder. If you delete that, all the light information will reset!