Fixing Stuck or Wrong Lighting After Installing ScalableLux

ScalableLux replaces Minecraft's light engine, so if you install it on an existing world you may occasionally see dark patches indoors, glowing spots that should be dark, or chunks that never finish lighting. These are almost always stale light data rather than a broken mod.

Force a relight of the affected area

The quickest fix is to make the game recalculate light for the problem region. Place and then break a light source (a torch is fine) directly in the affected area — this queues a light update for that block and its neighbours. For larger zones, place a torch at each corner of the dark region. If the area is huge, walk through it while holding a light source so each chunk you enter gets touched.

When that is not enough

If patches persist across restarts, the stored light data in the region files is likely inconsistent. Back up the world first, then use a chunk-editing tool to delete the affected chunks so they regenerate with fresh lighting. On a server, you can also try unloading and reloading the region by moving far away and returning. If problems only appear with parallel updates enabled, disable that option — the sequential path is more conservative about edge cases.