diff --git a/SCClassLibrary/Common/Collections/String.sc b/SCClassLibrary/Common/Collections/String.sc
index a64ef8c536e..859ae44caaa 100644
--- a/SCClassLibrary/Common/Collections/String.sc
+++ b/SCClassLibrary/Common/Collections/String.sc
@@ -240,6 +240,7 @@ String[char] : RawArray {
 
 	escapeChar { arg charToEscape; // $"
 		_String_EscapeChar
+		^this.primitiveFailed;
 	}
 	shellQuote {
 		^"'"++this.replace("'","'\\''")++"'"
@@ -292,7 +293,7 @@ String[char] : RawArray {
 	*readNew { arg file;
 		^file.readAllString;
 	}
-	prCat { arg aString; _ArrayCat }
+	prCat { arg aString; _ArrayCat; ^this.primitiveFailed; }
 
 	printOn { arg stream;
 		stream.putAll(this);
diff --git a/SCClassLibrary/Common/Control/MIDIOut.sc b/SCClassLibrary/Common/Control/MIDIOut.sc
index 4eb6c616d48..51288e57b2b 100644
--- a/SCClassLibrary/Common/Control/MIDIOut.sc
+++ b/SCClassLibrary/Common/Control/MIDIOut.sc
@@ -323,9 +323,11 @@ MIDIIn {
 	}
 	*connectByUID {arg inport, uid;
 		_ConnectMIDIIn
+		^this.primitiveFailed;
 	}
 	*disconnectByUID {arg inport, uid;
 		_DisconnectMIDIIn
+		^this.primitiveFailed;
 	}
 
 	*prDispatchEvent { arg eventList, status, port, chan, b, c;
@@ -450,6 +452,7 @@ MIDIOut {
 
 	send { arg outport, uid, len, hiStatus, loStatus, a=0, b=0, late;
 		_SendMIDIOut
+		^this.primitiveFailed;
 	}
 
 	prSysex { arg uid, packet;
diff --git a/SCClassLibrary/Common/Control/NetAddr.sc b/SCClassLibrary/Common/Control/NetAddr.sc
index fadd34d6d4c..ff8a2ac9d2b 100644
--- a/SCClassLibrary/Common/Control/NetAddr.sc
+++ b/SCClassLibrary/Common/Control/NetAddr.sc
@@ -17,10 +17,12 @@ NetAddr {
 
 	*langPort {
 		_GetLangPort
+		^this.primitiveFailed;
 	}
 
 	*matchLangIP {|ipstring|
 		_MatchLangIP
+		^this.primitiveFailed;
 	}
 	*localEndPoint {
 		^this.new(this.langIP, this.langPort)
diff --git a/SCClassLibrary/Common/Control/SerialPort.sc b/SCClassLibrary/Common/Control/SerialPort.sc
index 02fb7f086a0..3a65acf04c0 100644
--- a/SCClassLibrary/Common/Control/SerialPort.sc
+++ b/SCClassLibrary/Common/Control/SerialPort.sc
@@ -100,6 +100,7 @@ SerialPort
 	// rx errors since last query
 	rxErrors {
 		_SerialPort_RXErrors
+		^this.primitiveFailed;
 	}
 
 	// always blocks
diff --git a/SCClassLibrary/Common/Core/Symbol.sc b/SCClassLibrary/Common/Core/Symbol.sc
index ffea7254b15..3d789af681f 100644
--- a/SCClassLibrary/Common/Core/Symbol.sc
+++ b/SCClassLibrary/Common/Core/Symbol.sc
@@ -39,14 +39,17 @@ Symbol {
 	}
 	isClassName {
 		_SymbolIsClassName
+		^this.primitiveFailed;
 		// returns true if first character of symbol is a capital letter
 	}
 	isMetaClassName {
 		_SymbolIsMetaClassName
+		^this.primitiveFailed;
 		// returns true if there is a meta class by this name
 	}
 	isPrefix { | other |
 		_SymbolIsPrefix
+		^this.primitiveFailed;
 	}
 	isPrimitiveName {
 		// returns true if symbol is a valid primitive name
diff --git a/SCClassLibrary/Common/GUI/Base/QView.sc b/SCClassLibrary/Common/GUI/Base/QView.sc
index f1e57beaef1..1c545de5aa7 100644
--- a/SCClassLibrary/Common/GUI/Base/QView.sc
+++ b/SCClassLibrary/Common/GUI/Base/QView.sc
@@ -542,6 +542,7 @@ View : QObject {
 
 	*setGlobalEventEnabled { arg event, enabled;
 		_QWidget_SetGlobalEventEnabled
+		^this.primitiveFailed;
 	}
 
 	initView { arg parent;
diff --git a/SCClassLibrary/Common/GUI/Base/QWindow.sc b/SCClassLibrary/Common/GUI/Base/QWindow.sc
index 52c3bf4c7c0..4a4288bd2ba 100644
--- a/SCClassLibrary/Common/GUI/Base/QWindow.sc
+++ b/SCClassLibrary/Common/GUI/Base/QWindow.sc
@@ -84,10 +84,12 @@ Window
 
 	*screenBounds {
 		_QWindow_ScreenBounds
+		^this.primitiveFailed;
 	}
 
 	*availableBounds {
 		_QWindow_AvailableGeometry
+		^this.primitiveFailed;
 	}
 
 	*closeAll {
diff --git a/SCClassLibrary/Common/GUI/iphone/Base/GUIScreen.sc b/SCClassLibrary/Common/GUI/iphone/Base/GUIScreen.sc
index 70324c0792d..70cdb1e700b 100644
--- a/SCClassLibrary/Common/GUI/iphone/Base/GUIScreen.sc
+++ b/SCClassLibrary/Common/GUI/iphone/Base/GUIScreen.sc
@@ -103,6 +103,7 @@ SCWindow {
 
 	prSetAlwaysOnTop{|boolean=true|
 		_SCWindow_AlwaysOnTop
+		^this.primitiveFailed;
 	}
 
 	acceptsClickThrough_{|boolean=true|
@@ -112,6 +113,7 @@ SCWindow {
 
 	prSetAcceptsClickThrough{|boolean=true|
 		_SCWindow_AcceptsClickThrough
+		^this.primitiveFailed;
 	}
 
 	refresh {
diff --git a/SCClassLibrary/DefaultLibrary/Main.sc b/SCClassLibrary/DefaultLibrary/Main.sc
index 8dbf89b796d..5f67f5b429c 100644
--- a/SCClassLibrary/DefaultLibrary/Main.sc
+++ b/SCClassLibrary/DefaultLibrary/Main.sc
@@ -96,7 +96,7 @@ Main : Process {
 
 	prOpenUDPPort {|portNum|
 		_OpenUDPPort
-		^false
+		^this.primitiveFailed;
 	}
 
 //	override in platform specific extension
diff --git a/SCClassLibrary/Platform/linux/extMIDIOut.sc b/SCClassLibrary/Platform/linux/extMIDIOut.sc
index cd3a0667c74..fe46d1044ba 100644
--- a/SCClassLibrary/Platform/linux/extMIDIOut.sc
+++ b/SCClassLibrary/Platform/linux/extMIDIOut.sc
@@ -105,8 +105,10 @@
 	}
 	*connectByUID {arg outport, uid;
 		_ConnectMIDIOut
+		^this.primitiveFailed;
 	}
 	*disconnectByUID {arg outport, uid;
 		_DisconnectMIDIOut
+		^this.primitiveFailed;
 	}
 }
diff --git a/SCClassLibrary/scide_scqt/ScIDE.sc b/SCClassLibrary/scide_scqt/ScIDE.sc
index 7ab53d6d612..a788a130e89 100644
--- a/SCClassLibrary/scide_scqt/ScIDE.sc
+++ b/SCClassLibrary/scide_scqt/ScIDE.sc
@@ -789,6 +789,7 @@ Document {
 
 	prGetSelectionStart {|id|
 		_ScIDE_GetDocSelectionStart
+		^this.primitiveFailed;
 	}
 
 	selectionSize {
@@ -797,6 +798,7 @@ Document {
 
 	prGetSelectionRange {|id|
 		_ScIDE_GetDocSelectionRange
+		^this.primitiveFailed;
 	}
 
 	string { | rangestart, rangesize = 1 |