feldspirit

First and last bump for this topic. Did I forget to include some information/log in this report? Also tested Risugami's modloader - it works perfectly fine in this respect. (Or is it not okay to mention that here?)

Mods: Minecraft Forge only Mobs don't spawn on upper stone slabs block (ID 44) as well as upside-down stairs (block ID 134) but have no problem spawning on upper wood slabs (block ID 126). Mobs spawn on all of those blocks (44, 134 and 126) upon reverting to a vanilla .jar. This bug exists on versions 1.4.5 - build 6.4.2.448. 1.4.6 - builds 6.5.0.467, 6.5.0.470, 6.5.0.472 and 6.5.0.486. Probably also exists on version in between, but I didn't test those. Edit: Resolved as of 1.4.6, build 6.5.0.487. I made 5 floors with the following block IDs: 1 (stone) 134:7 (upside-down spruce wood stairs) 126:9 (upper spruce slab) 44:13 (upper stone brick slab) 44:0 (lower stone slab) One torch was placed on each floor where possible just to show that it's a top half, not a bottom half block. Results in 1.4.6 vanilla: 1 (stone) - mobs spawn 134:7 (upside-down spruce wood stairs) - mobs spawn 126:9 (upper spruce slab) - mobs spawn 44:13 (upper stone brick slab) - mobs spawn 44:0 (lower stone slab) - mobs don't spawn 1 (stone) - mobs spawn 134:7 (upside-down spruce wood stairs) - mobs don't spawn 126:9 (upper spruce slab) - mobs spawn 44:13 (upper stone brick slab) - mobs don't spawn 44:0 (lower stone slab) - mobs don't spawn This is in 1.4.6 vanilla: This is in 1.4.6, build 6.5.0.470. Whoops, forgot the log.