diff --git a/src/d_defcvars.cpp b/src/d_defcvars.cpp
index a53fbe0a34..4d38e57fa0 100644
--- a/src/d_defcvars.cpp
+++ b/src/d_defcvars.cpp
@@ -34,6 +34,8 @@
 #include "c_console.h"
 #include "d_main.h"
 #include "version.h"
+#include "d_defcvars.h"
+
 
 void D_GrabCVarDefaults()
 {
@@ -104,9 +106,30 @@ void D_GrabCVarDefaults()
 					break;
 			}
 
+			bool blacklisted = false;
+			SHOULD_BLACKLIST(disablecrashlog)
+			SHOULD_BLACKLIST(gl_control_tear)
+			SHOULD_BLACKLIST(in_mouse)
+			SHOULD_BLACKLIST(joy_dinput)
+			SHOULD_BLACKLIST(joy_ps2raw)
+			SHOULD_BLACKLIST(joy_xinput)
+			SHOULD_BLACKLIST(k_allowfullscreentoggle)
+			SHOULD_BLACKLIST(k_mergekeys)
+			SHOULD_BLACKLIST(m_swapbuttons)
+			SHOULD_BLACKLIST(queryiwad_key)
+			SHOULD_BLACKLIST(vid_gpuswitch)
+			SHOULD_BLACKLIST(vr_enable_quadbuffered)
+
 			var = FindCVar(CurrentFindCVar, NULL);
-			if (var != NULL)
+
+			if (blacklisted)
 			{
+				sc.ScriptMessage("Cannot set cvar default for blacklisted cvar '%s'", sc.String);
+				sc.MustGetString(); // to ignore the value of the cvar
+			}
+			else if (var != NULL)
+			{
+
 				if (var->GetFlags() & CVAR_ARCHIVE)
 				{
 					UCVarValue val;
@@ -115,14 +138,16 @@ void D_GrabCVarDefaults()
 					val.String = const_cast<char*>(sc.String);
 					var->SetGenericRepDefault(val, CVAR_String);
 				}
-				else
+				else 
 				{
 					sc.ScriptMessage("Cannot set cvar default for non-config cvar '%s'", sc.String);
+					sc.MustGetString(); // to ignore the value of the cvar
 				}
 			}
 			else
 			{
 				sc.ScriptMessage("Unknown cvar '%s' in defcvars", sc.String);
+				sc.MustGetString(); // to ignore the value of the cvar
 			}
 		}
 	}
diff --git a/src/d_defcvars.h b/src/d_defcvars.h
new file mode 100644
index 0000000000..73f110c707
--- /dev/null
+++ b/src/d_defcvars.h
@@ -0,0 +1,27 @@
+//-----------------------------------------------------------------------------
+// Copyright 2021 Rachael Alexanderson
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see http://www.gnu.org/licenses/
+//
+//
+// DESCRIPTION:
+//		defcvars loader split from d_main.cpp
+//
+//-----------------------------------------------------------------------------
+
+#define SHOULD_BLACKLIST(name) \
+	if (#name[0]==CurrentFindCVar[0]) \
+		if (strcmp(CurrentFindCVar, #name) == 0) \
+			blacklisted = true;
+