i’ve been trying to solve this problem for few hours. i have no others idea… i tried to make a new skybox, make it bigger, smaller etc but it didn’t help. there is no leak at all. i followed that red line and there is nothing… it start outside map, and ends outside map.
anyone had similar problem and have idea how to fix it?
the red line may seem to go nowhere but I found it led to an entity with a messed up origin way off the grid after 10min following the damn thing
so yea do what deaths says
Either that or make a box around your map so you just pass the edges, then use the select inside tool and repeat. 
Or maybe there is an entity above the skybox? So it can draw the red line too Check if there is exactly nothing at this point/what’s in the line’s beginning.
Also check if this line is not starting at [0 0 0]. It might be a screwed up entity with no origin.
hi i am using gtk radiant (and quark occasionally).i use q3 map2 to compile the maps to bsp.
i use irrlicht game engine.
whenever i compile the map in gtk radiant with only -bsp -meta option it shows a “map leak error”…
i read a tutorial telling that “<mapname>.lin” file can be used to find out the leak related co-ordinates from gtk radiant,they call it a pointfile.
the tutorial said that i have to run q3map2 with -leaktest option enabled to generate the pointfile with co-ordinates of the leak…
i tried but the compilation stops when a leak is detected.
is there another way to generate the pointfile.please give me the compilation option i have to use to get the file as output.
i just had the same problem as Indy last week… somehow no matter what i did, there was leaking error and red line with 2 points… and that line went right through my “skybox”, FROM THE MIDDLE OF IT!! like wtf… then i made a bigger “skybox”, just a big brush cube around my map and hollowed it, still the same problem and about the same place, then i went massive, even bigger cube like 50% of the maximum possible in radiant… then i made a big brush around that supposedly leaky point… selected complete tall and found nothing, but still pushed the delete button and afterwards i made a brush cleanup… next time i complied it didnt show any leak error… hope this helped u a bit…
nope sry… last 3 days went to drinking… i thought he had made a new topic meanwhile… 
Sorry, l had same problem with tree model going through ground down, when compiling l get message map is leaked, skybox was perfect. Try to find in this place is not such model. Sorry for my English
Easiest way to fix: draw a box the same dimensions as the furthest extents as your map… so it hits everything that you want. Then use Select Inside. Then press I to invert selection. Delete.