--- a/src/in_ncsf/XSFConfig_NCSF.cpp
+++ b/src/in_ncsf/XSFConfig_NCSF.cpp
@@ -14,7 +14,7 @@
 #include "XSFConfig_NCSF.h"
 #include "XSFPlayer_NCSF.h"
 #include "convert.h"
-#ifdef _DEBUG
+#ifndef NDEBUG
 # include <cstdint>
 # include "SSEQPlayer/common.h"
 # include "SSEQPlayer/consts.h"
@@ -40,7 +40,7 @@
 }
 
 XSFConfig_NCSF::XSFConfig_NCSF() : XSFConfig(), interpolation(0), mutes()
-#ifdef _DEBUG
+#ifndef NDEBUG
 	, soundViewData()
 #endif
 {
@@ -134,7 +134,7 @@
 		"Utilizes code adapted from the FeOS Sound System library by fincs, git revision 5204c55 on GitHub, for audio playback.").c_str(), ConvertFuncs::StringToWString(XSFConfig::commonName + " v" + XSFConfig::versionNumber).c_str(), MB_OK);
 }
 
-#ifdef _DEBUG
+#ifndef NDEBUG
 INT_PTR CALLBACK XSFConfig_NCSF::SoundViewDialogProc(HWND hwndDlg, UINT uMsg, WPARAM wParam, LPARAM lParam)
 {
 	auto data = reinterpret_cast<SoundViewData *>(GetWindowLongW(hwndDlg, DWLP_USER));

--- a/src/in_ncsf/XSFConfig_NCSF.h
+++ b/src/in_ncsf/XSFConfig_NCSF.h
@@ -9,7 +9,7 @@
 
 #include <bitset>
 #include <string>
-#ifdef _DEBUG
+#ifndef NDEBUG
 # include <algorithm>
 # include <memory>
 # include <cstdint>
@@ -21,7 +21,7 @@
 class XSFConfig_NCSF;
 class XSFPlayer_NCSF;
 
-#ifdef _DEBUG
+#ifndef NDEBUG
 struct SoundViewData
 {
 	XSFConfig_NCSF *config;
@@ -58,7 +58,7 @@
 	void SaveSpecificConfigDialog(HWND hwndDlg) override;
 	void CopySpecificConfigToMemory(XSFPlayer *xSFPlayer, bool preLoad) override;
 
-#ifdef _DEBUG
+#ifndef NDEBUG
 	std::unique_ptr<SoundViewData> soundViewData;
 
 	static INT_PTR CALLBACK SoundViewDialogProc(HWND hwndDlg, UINT uMsg, WPARAM wParam, LPARAM lParam);
@@ -66,7 +66,7 @@
 public:
 	void About(HWND parent) override;
 
-#ifdef _DEBUG
+#ifndef NDEBUG
 	void CallSoundView(XSFPlayer *xSFPlayer, HINSTANCE hInstance, HWND hwndParent);
 	void RefreshSoundView();
 	void CloseSoundView();

--- a/src/in_ncsf/XSFPlayer_NCSF.cpp
+++ b/src/in_ncsf/XSFPlayer_NCSF.cpp
@@ -125,7 +125,7 @@
 }
 #endif
 
-#ifdef _DEBUG
+#ifndef NDEBUG
 static HANDLE soundViewThreadHandle = INVALID_HANDLE_VALUE;
 static bool killSoundViewThread;
 
@@ -150,7 +150,7 @@
 
 XSFPlayer_NCSF::~XSFPlayer_NCSF()
 {
-#ifdef _DEBUG
+#ifndef NDEBUG
 	killSoundViewThread = true;
 	if (WaitForSingleObject(soundViewThreadHandle, 2000) == WAIT_TIMEOUT)
 	{
@@ -167,7 +167,7 @@
 	if (!this->LoadNCSF())
 		return false;
 
-#ifdef _DEBUG
+#ifndef NDEBUG
 	killSoundViewThread = false;
 	soundViewThreadHandle = CreateThread(nullptr, 0, soundViewThread, this, 0, nullptr);
 #endif
@@ -258,7 +258,7 @@
 	this->mutes = newMutes;
 }
 
-#ifdef _DEBUG
+#ifndef NDEBUG
 const Channel &XSFPlayer_NCSF::GetChannel(std::size_t chanNum) const
 {
 	return this->player.channels[chanNum];

--- a/src/in_ncsf/XSFPlayer_NCSF.h
+++ b/src/in_ncsf/XSFPlayer_NCSF.h
@@ -14,7 +14,7 @@
 #include <memory>
 #include <string>
 #include <vector>
-#ifdef _DEBUG
+#ifndef NDEBUG
 # include <cstddef>
 #endif
 #include <cstdint>
@@ -47,7 +47,7 @@
 
 	void SetInterpolation(unsigned interpolation);
 	void SetMutes(const std::bitset<16> &newMutes);
-#ifdef _DEBUG
+#ifndef NDEBUG
 	const Channel &GetChannel(std::size_t chanNum) const;
 #endif
 };