Hi Dr_Jerm,
I remember getting the failing to save during the 4.14 previews a couple of times, but I’ve not had it since the 4.14.0 release. If you happen to have any repro steps that make this more reproducible feel free to let me know.
I also don’t see the issue with map sizes quadrupling or even doubling.
As an example, I used the default map with the chairs and table. I copied these around with the floor mesh so that I had a few hundred. I set the Lightmap Resolution for these to be 256 just so they had some weight in size. In 4.13 when I built the lighting the map size came out to 113.37mb. In 4.14 I rebuilt the lighting so that it would break out the lighting for the _BuildData file. When checking the size on this it was 113.6mb and the Map file was now at 1.547mb. I rebuilt lighting a few times and restarted and did this but didn’t see any change in the size of the build data.
Are you using any particular setup for your levels, like sub-levels with stored assets and if so how many? How many meshes, approximately, are you using in your level? I’d be curious if you see this same behavior in a blank level vs your current level, since I’m not seeing it in my test.
Thanks!
Tim