ok I discovered the problem was me! I took my 4.11 file yesterday night and brought it to the same setting of my 4.10 file: over all I deleted all the light portals and tried to rebuild → it worked! and as you said now it doesn’t give error again! so my 5 portals were so heavy to make a long long (very long) building time! at this time I don’t know if work with portal or overhaul the beselightmass.ini
btw again I’m sorry for all this mess!