diff --git a/Common/MemArena.cpp b/Common/MemArena.cpp
index 82861775bc..ef65551614 100644
--- a/Common/MemArena.cpp
+++ b/Common/MemArena.cpp
@@ -215,8 +215,10 @@ u8* MemArena::Find4GBBase()
 #ifdef _M_X64
 #ifdef _WIN32
 	// 64 bit
-	u8* base = (u8*)VirtualAlloc(0, 0xE1000000, MEM_RESERVE, PAGE_READWRITE);
-	VirtualFree(base, 0, MEM_RELEASE);
+	u8 *base = (u8*)VirtualAlloc(0, 0xE1000000, MEM_RESERVE, PAGE_READWRITE);
+	if (base) {
+		VirtualFree(base, 0, MEM_RELEASE);
+	}
 	return base;
 #else
 	// Very precarious - mmap cannot return an error when trying to map already used pages.
diff --git a/Common/x64Emitter.h b/Common/x64Emitter.h
index db7d67dea8..e78166f9b3 100644
--- a/Common/x64Emitter.h
+++ b/Common/x64Emitter.h
@@ -34,7 +34,7 @@
 namespace Gen
 {
 
-enum X64Reg
+enum X64Reg : u32
 {
 	EAX = 0, EBX = 3, ECX = 1, EDX = 2,
 	ESI = 6, EDI = 7, EBP = 5, ESP = 4,
diff --git a/Core/FileLoaders/RamCachingFileLoader.cpp b/Core/FileLoaders/RamCachingFileLoader.cpp
index 7f56774a81..b4f9453941 100644
--- a/Core/FileLoaders/RamCachingFileLoader.cpp
+++ b/Core/FileLoaders/RamCachingFileLoader.cpp
@@ -223,7 +223,7 @@ void RamCachingFileLoader::StartReadAhead(s64 pos) {
 
 			for (u32 i = cacheStartPos; i <= cacheEndPos; ++i) {
 				if (blocks_[i] == 0) {
-					SaveIntoCache(i << BLOCK_SHIFT, BLOCK_SIZE * BLOCK_READAHEAD);
+					SaveIntoCache((u64)i << BLOCK_SHIFT, BLOCK_SIZE * BLOCK_READAHEAD);
 					break;
 				}
 			}
diff --git a/Core/HLE/ReplaceTables.cpp b/Core/HLE/ReplaceTables.cpp
index 9a5a434995..5fc1da5d7d 100644
--- a/Core/HLE/ReplaceTables.cpp
+++ b/Core/HLE/ReplaceTables.cpp
@@ -477,7 +477,7 @@ static int Replace_dl_write_matrix() {
 		return 60;
 	}
 
-	u32 matrix;
+	u32 matrix = 0;
 	int count = 12;
 	switch (PARAM(1)) {
 	case 3:
diff --git a/Core/HLE/sceAudiocodec.cpp b/Core/HLE/sceAudiocodec.cpp
index 76d18df677..83d70dc343 100644
--- a/Core/HLE/sceAudiocodec.cpp
+++ b/Core/HLE/sceAudiocodec.cpp
@@ -180,6 +180,8 @@ void __sceAudiocodecDoState(PointerWrap &p){
 			// loadstate if audioList is nonempty
 			auto codec_ = new int[count];
 			auto ctxPtr_ = new u32[count];
+			// These sizeof(pointers) are wrong, but kept to avoid breaking on old saves.
+			// They're not used in new savestates.
 			p.DoArray(codec_, s >= 2 ? count : (int)ARRAY_SIZE(codec_));
 			p.DoArray(ctxPtr_, s >= 2 ? count : (int)ARRAY_SIZE(ctxPtr_));
 			for (int i = 0; i < count; i++) {
diff --git a/Core/HLE/sceKernelThread.cpp b/Core/HLE/sceKernelThread.cpp
index 6b43be3cd0..4c9395cfe2 100644
--- a/Core/HLE/sceKernelThread.cpp
+++ b/Core/HLE/sceKernelThread.cpp
@@ -1656,7 +1656,7 @@ static void __ReportThreadQueueEmpty() {
 	int idleStatus1 = -1;
 	if (idleThread1) {
 		idleThread1->GetQuickInfo(idleDescription1, sizeof(idleDescription1));
-		idleStatus1 = idleThread0->nt.status;
+		idleStatus1 = idleThread1->nt.status;
 	} else {
 		sprintf(idleDescription1, "DELETED");
 	}
diff --git a/Core/MIPS/x86/RegCache.h b/Core/MIPS/x86/RegCache.h
index 9b3ae2f195..fe7cc43a21 100644
--- a/Core/MIPS/x86/RegCache.h
+++ b/Core/MIPS/x86/RegCache.h
@@ -35,9 +35,9 @@ namespace X64JitConstants {
 	const int NUM_MIPS_GPRS = 36;
 
 #ifdef _M_X64
-	const int NUM_X_REGS = 16;
+	const u32 NUM_X_REGS = 16;
 #elif _M_IX86
-	const int NUM_X_REGS = 8;
+	const u32 NUM_X_REGS = 8;
 #endif
 }
 
diff --git a/Core/SaveState.cpp b/Core/SaveState.cpp
index ee8f3d1aaa..1155de1c61 100644
--- a/Core/SaveState.cpp
+++ b/Core/SaveState.cpp
@@ -646,7 +646,8 @@ namespace SaveState
 				break;
 
 			case SAVESTATE_SAVE_SCREENSHOT:
-				if (!TakeGameScreenshot(op.filename.c_str(), SCREENSHOT_JPG, SCREENSHOT_RENDER)) {
+				callbackResult = TakeGameScreenshot(op.filename.c_str(), SCREENSHOT_JPG, SCREENSHOT_RENDER);
+				if (!callbackResult) {
 					ERROR_LOG(COMMON, "Failed to take a screenshot for the savestate! %s", op.filename.c_str());
 				}
 				break;
diff --git a/ext/native/gfx_es2/draw_text.cpp b/ext/native/gfx_es2/draw_text.cpp
index 03de087229..c3352307f7 100644
--- a/ext/native/gfx_es2/draw_text.cpp
+++ b/ext/native/gfx_es2/draw_text.cpp
@@ -81,7 +81,7 @@ uint32_t TextDrawer::SetFont(const char *fontName, int size, int flags) {
 	else
 		fname = L"Tahoma";
 
-	uint32_t fontHash = hash::Fletcher((const uint8_t *)fontName, strlen(fontName));
+	uint32_t fontHash = fontName ? hash::Fletcher((const uint8_t *)fontName, strlen(fontName)) : 0;
 	fontHash ^= size;
 	fontHash ^= flags << 10;