diff --git a/src/maploader/renderinfo.cpp b/src/maploader/renderinfo.cpp
index 32ec955ac1..4faeb0eabe 100644
--- a/src/maploader/renderinfo.cpp
+++ b/src/maploader/renderinfo.cpp
@@ -709,7 +709,7 @@ void MapLoader::InitRenderInfo()
 	PrepareSectorData();
 	InitVertexData();
 	FloodSectorStacks();
-	TArray<int> checkmap(Level->vertexes.Size());
+	TArray<int> checkmap(Level->vertexes.Size(), true);
 	memset(checkmap.Data(), -1, sizeof(int)*Level->vertexes.Size());
 	for(auto &sec : Level->sectors) 
 	{
diff --git a/src/p_saveg.cpp b/src/p_saveg.cpp
index 2ff6b9bf90..adcd093fda 100644
--- a/src/p_saveg.cpp
+++ b/src/p_saveg.cpp
@@ -374,7 +374,7 @@ FSerializer &FLevelLocals::SerializeSubsectors(FSerializer &arc, const char *key
 	auto numsubsectors = subsectors.Size();
 	if (arc.isWriting())
 	{
-		TArray<char> encoded(1 + (numsubsectors + 5) / 6);
+		TArray<char> encoded(1 + (numsubsectors + 5) / 6, true);
 		int p = 0;
 		for (unsigned i = 0; i < numsubsectors; i += 6)
 		{
diff --git a/src/r_data/r_sections.cpp b/src/r_data/r_sections.cpp
index 998945aa64..7ffe3cf0f4 100644
--- a/src/r_data/r_sections.cpp
+++ b/src/r_data/r_sections.cpp
@@ -803,6 +803,21 @@ public:
 				sub.section = bestfit;
 			}
 		}
+
+		// Set all empty sectors' initial index to 0, so that we do not have to range-check each access.
+		for (unsigned i = 0; i < Level->sectors.Size(); i++)
+		{
+			if (Level->sections.firstSectionForSectorPtr[i] < 0)
+			{
+				Level->sections.firstSectionForSectorPtr[i] = 0;
+				if (Level->sections.numberOfSectionForSectorPtr[i] > 0)
+				{
+					// This should never happen.
+					Printf("Warning: Sector %d has a non-empty section list with no address\n", i);
+					Level->sections.numberOfSectionForSectorPtr = 0;
+				}
+			}
+		}
 	}
 
 };
diff --git a/src/r_data/r_translate.h b/src/r_data/r_translate.h
index f050f788e7..d71c64d44b 100644
--- a/src/r_data/r_translate.h
+++ b/src/r_data/r_translate.h
@@ -83,7 +83,7 @@ struct FRemapTable
 
 	uint8_t Remap[256];				// For the software renderer
 	PalEntry Palette[256];			// The ideal palette this maps to
-	FUniquePalette *Native;		// The index into the list of unique palettes (this is to avoid frequent texture recreation with changing ACS translations)
+	FUniquePalette *Native = nullptr;		// The index into the list of unique palettes (this is to avoid frequent texture recreation with changing ACS translations)
 	//int crc32;
 	int NumEntries;				// # of elements in this table (usually 256)
 	bool Inactive = false;				// This table is inactive and should be treated as if it was passed as NULL