diff --git a/src/common/audio/music/music_config.cpp b/src/common/audio/music/music_config.cpp
index efdb05637..5ea5e97d9 100644
--- a/src/common/audio/music/music_config.cpp
+++ b/src/common/audio/music/music_config.cpp
@@ -95,7 +95,7 @@ CUSTOM_CVAR(Bool, adl_use_custom_bank, false, CVAR_ARCHIVE | CVAR_VIRTUAL)
 	FORWARD_BOOL_CVAR(adl_use_custom_bank);
 }
 
-CUSTOM_CVAR(String, adl_custom_bank, "", CVAR_ARCHIVE | CVAR_VIRTUAL)
+CUSTOM_CVAR(String, adl_custom_bank, "", CVAR_ARCHIVE | CVAR_VIRTUAL | CVAR_SYSTEM_ONLY)
 {
 	FORWARD_STRING_CVAR(adl_custom_bank);
 }
@@ -111,12 +111,12 @@ CUSTOM_CVAR(Int, adl_volume_model, 0 /*ADLMIDI_VolumeModel_AUTO*/, CVAR_ARCHIVE
 //
 //==========================================================================
 
-CUSTOM_CVAR(String, fluid_lib, "", CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VIRTUAL)
+CUSTOM_CVAR(String, fluid_lib, "", CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VIRTUAL | CVAR_SYSTEM_ONLY)
 {
 	FORWARD_STRING_CVAR(fluid_lib);
 }
 
-CUSTOM_CVAR(String, fluid_patchset, GAMENAMELOWERCASE, CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VIRTUAL)
+CUSTOM_CVAR(String, fluid_patchset, GAMENAMELOWERCASE, CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VIRTUAL | CVAR_SYSTEM_ONLY)
 {
 	FORWARD_STRING_CVAR(fluid_patchset);
 }
@@ -278,7 +278,7 @@ CUSTOM_CVAR(String, opn_custom_bank, "", CVAR_ARCHIVE | CVAR_VIRTUAL)
 //==========================================================================
 
 
-CUSTOM_CVAR(String, midi_config, "", CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VIRTUAL)
+CUSTOM_CVAR(String, midi_config, "", CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VIRTUAL | CVAR_SYSTEM_ONLY)
 {
 	FORWARD_STRING_CVAR(gus_config);
 }
@@ -288,7 +288,7 @@ CUSTOM_CVAR(Bool, midi_dmxgus, false, CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VI
 	FORWARD_BOOL_CVAR(gus_dmxgus);
 }
 
-CUSTOM_CVAR(String, gus_patchdir, "", CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VIRTUAL)
+CUSTOM_CVAR(String, gus_patchdir, "", CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VIRTUAL | CVAR_SYSTEM_ONLY)
 {
 	FORWARD_STRING_CVAR(gus_patchdir);
 }
@@ -395,7 +395,7 @@ CUSTOM_CVAR(Float, timidity_min_sustain_time, 5000.f, CVAR_ARCHIVE | CVAR_GLOBAL
 }
 #endif
 
-CUSTOM_CVAR(String, timidity_config, GAMENAMELOWERCASE, CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VIRTUAL)
+CUSTOM_CVAR(String, timidity_config, GAMENAMELOWERCASE, CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VIRTUAL | CVAR_SYSTEM_ONLY)
 {
 	FORWARD_STRING_CVAR(timidity_config);
 }
@@ -406,7 +406,7 @@ CUSTOM_CVAR(String, timidity_config, GAMENAMELOWERCASE, CVAR_ARCHIVE | CVAR_GLOB
 //
 //==========================================================================
 
-CUSTOM_CVAR(String, wildmidi_config, "", CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VIRTUAL)
+CUSTOM_CVAR(String, wildmidi_config, "", CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_VIRTUAL | CVAR_SYSTEM_ONLY)
 {
 	FORWARD_STRING_CVAR(wildmidi_config);
 }
diff --git a/src/common/console/c_cvars.h b/src/common/console/c_cvars.h
index c52af0aeb..ccc3cfa6a 100644
--- a/src/common/console/c_cvars.h
+++ b/src/common/console/c_cvars.h
@@ -75,6 +75,8 @@ enum
 	CVAR_CONFIG_ONLY		= 1 << 18, // do not save var to savegame and do not send it across network.
 	CVAR_ZS_CUSTOM			= 1 << 19, // Custom CVar backed by a ZScript class
 	CVAR_ZS_CUSTOM_CLONE	= 1 << 20, // Clone of a Custom ZScript CVar
+	
+	CVAR_SYSTEM_ONLY		= 1 << 21, // System-related cvar that should only ever be changed by the user
 };
 
 enum ECVarType
diff --git a/src/common/menu/savegamemanager.cpp b/src/common/menu/savegamemanager.cpp
index 929d631d1..efb5a02af 100644
--- a/src/common/menu/savegamemanager.cpp
+++ b/src/common/menu/savegamemanager.cpp
@@ -49,7 +49,7 @@
 #include "m_argv.h"
 #include "i_specialpaths.h"
 
-CVAR(String, save_dir, "", CVAR_ARCHIVE | CVAR_GLOBALCONFIG);
+CVAR(String, save_dir, "", CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_SYSTEM_ONLY);
 FString SavegameFolder;
 CVAR(Int, save_sort_order, 0, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
 
diff --git a/src/d_defcvars.cpp b/src/d_defcvars.cpp
index bcd8ad194..ca274a7fe 100644
--- a/src/d_defcvars.cpp
+++ b/src/d_defcvars.cpp
@@ -134,6 +134,9 @@ void D_GrabCVarDefaults()
 
 			var = FindCVar(CurrentFindCVar.GetChars(), NULL);
 
+			if (var->GetFlags() & CVAR_SYSTEM_ONLY)
+				blacklisted = true;
+
 			if (blacklisted)
 			{
 				sc.ScriptMessage("Cannot set cvar default for blacklisted cvar '%s'", sc.String);