Lighting needs to rebuilt

Hey everyone. I’m still kind of new to ue and i’m facing a weird problem in my first project.
When i build the lights every thing works perfectly in any session i open
But when i do so in a specific project the cpu usage jumps only to almost 25% and the memory usage(ram) jump to 100%
After about 15 mins the build is done but the message is still there "LIGHTING NEED TO BE REBUILT(728 unbuilt objects)
I’m using a core i7 7700 cpu 3.6 ghz
32 gb ram
Gtx 1060 6 gb
I’ve been searching for almost a week for an answer but nothing

I figuered out one last thing. I tried to delete the meshs in the same project and the lighting build process worked perfectly. When i don’t delete the meshs the “building lighting” process get stuck on 0% and then finish sudenly maybe cancel by itself i’m not sure.