so i have a streaming level named Maingame. and there is persitant level named Bomb. so in order to edit thing i generally open my Maingame level, but when i press the ‘save current’ button on top left corner of viewport, mapbuiltdata.uasset of maingame level get corrupt. before corruption it was 32mb, after getting corrupt it gets reduced to 1kb which is a clear sign of corruption. plus because of corruption unreal is not even loading that file. luckily because of this problem i am always keeping an updated back up of that file(which is not corrupted), so when it gets corrupt i replace it with my backup one before starting unreal. now what happens is that when unreal fails to load that file i lose all of that level’s light built and reflection data. so i require little help.
i am using version 4.14.3
EDIT: i tried to replicate my problem in different project and everything worked fine but not in my main project. then i thought may be builtdata’s size has to do with it so i duplicated my project and deleted out 90% objects and rebuilt the light hence i reduced builtdata size from 35mb to 2mb. and then i retried my the save thing after restarting my project. and again it got corrupted. as long as i don’t press the save current button everything seems fine, but i can’t stop my self pressing that because lol… we have to save the change that we made.