Aha finally I can help YAY. Yes well the exact same problem happened to me (probably some people can remember my thread "argh my eyes are burning - a radiant lighting problem"). I have a feeling that either you're not doing bsp_fullvis, or radiant isn't doing the light section for you. Can you post what the console returns when you're bsp'ing it? There should be a section --BSP-- --VIS-- and --LIGHT--. If not, then there's something up. What i had to do was go to project settings and add 3 new commands to the bsp menu - one for each section.

Also, if you use GTKRadiant, go to Edit -> Prefences -> BSP Monitoring, and disable the BSP Monitoring. Cuz, when the Bsp Monitoring is enabled, some errors can be caused during compiling, especialy with light proces.

Well I have the bsp monitering off and it does --bsp-- --vis-- --light-- so I have no clue (also I'm doin' bsp fullvis).

*bump*
 

*bump* :agreed: MY BAD :agreed: !! *bump*

*bump* :agreed: ME VERY BAD :agreed: *bump*

I see that you're doing a huge-sized area. I had your probs like many others, and in one of these threads, it came out that big empty maps could cause a crash in lightning.
I dunno if since that, a clear and categorical solution have been found (I admit that every time I bsp my maps, I turn into a freeze Ice Rock -yeah, even me- fearing that f*** crash occure once again).
But while your map isn"t so hard, don't hesitate to re-start it before going too far in its structure...
I sincerely hope you won't have to, but don't forget this option... (pessimistic, eh ?)

That isn't my whole map *wicked grin*