diff --git a/source/WorldStorage/WSSAnvil.cpp b/source/WorldStorage/WSSAnvil.cpp
index 5d48ee1f5..f14d4918b 100644
--- a/source/WorldStorage/WSSAnvil.cpp
+++ b/source/WorldStorage/WSSAnvil.cpp
@@ -447,7 +447,7 @@ cChunkDef::BiomeMap * cWSSAnvil::LoadVanillaBiomeMapFromNBT(cChunkDef::BiomeMap
 	{
 		return NULL;
 	}
-	if (a_NBT.GetDataLength(a_TagIdx) != sizeof(*a_BiomeMap))
+	if (a_NBT.GetDataLength(a_TagIdx) != 16 * 16)
 	{
 		// The biomes stored don't match in size
 		return NULL;