diff --git a/client/common/cmdline.c b/client/common/cmdline.c
index a681d3d2e..e1a893f75 100644
--- a/client/common/cmdline.c
+++ b/client/common/cmdline.c
@@ -870,6 +870,8 @@ int freerdp_detect_windows_style_command_line_syntax(int argc, char** argv, int*
 	detect_status = 0;
 	CommandLineClearArgumentsA(args);
 	status = CommandLineParseArgumentsA(argc, (const char**) argv, args, flags, NULL, NULL, NULL);
+	if (status < 0)
+		return status;
 
 	arg = args;
 
@@ -903,6 +905,8 @@ int freerdp_detect_posix_style_command_line_syntax(int argc, char** argv, int* c
 	detect_status = 0;
 	CommandLineClearArgumentsA(args);
 	status = CommandLineParseArgumentsA(argc, (const char**) argv, args, flags, NULL, NULL, NULL);
+	if (status < 0)
+		return status;
 
 	arg = args;
 
@@ -945,7 +949,8 @@ BOOL freerdp_client_detect_command_line(int argc, char** argv, DWORD* flags)
 		*flags = COMMAND_LINE_SEPARATOR_COLON;
 		*flags |= COMMAND_LINE_SIGIL_SLASH | COMMAND_LINE_SIGIL_PLUS_MINUS;
 	}
-	else
+	/* Ignore legacy parsing in case there is an error in the command line. */
+	else if (old_cli_status >= 0)
 	{
 		if ((old_cli_status == 1) || ((old_cli_count > posix_cli_count) && (old_cli_status != -1)))
 		{
@@ -966,12 +971,7 @@ int freerdp_client_command_line_status_print(int argc, char** argv, rdpSettings*
 {
 	COMMAND_LINE_ARGUMENT_A* arg;
 
-	if (status == COMMAND_LINE_STATUS_PRINT_HELP)
-	{
-		freerdp_client_print_command_line_help(argc, argv);
-		return COMMAND_LINE_STATUS_PRINT_HELP;
-	}
-	else if (status == COMMAND_LINE_STATUS_PRINT_VERSION)
+	if (status == COMMAND_LINE_STATUS_PRINT_VERSION)
 	{
 		freerdp_client_print_version();
 		return COMMAND_LINE_STATUS_PRINT_VERSION;
@@ -1015,6 +1015,11 @@ int freerdp_client_command_line_status_print(int argc, char** argv, rdpSettings*
 
 		return COMMAND_LINE_STATUS_PRINT;
 	}
+	else if (status < 0)
+	{
+		freerdp_client_print_command_line_help(argc, argv);
+		return COMMAND_LINE_STATUS_PRINT_HELP;
+	}
 
 	return 0;
 }
@@ -1043,6 +1048,8 @@ int freerdp_client_parse_command_line_arguments(int argc, char** argv, rdpSettin
 		CommandLineClearArgumentsA(args);
 		status = CommandLineParseArgumentsA(argc, (const char**) argv, args, flags, settings,
 				freerdp_client_command_line_pre_filter, freerdp_client_command_line_post_filter);
+		if (status < 0)
+			return status;
 	}
 
 
@@ -1626,7 +1633,8 @@ int freerdp_client_parse_command_line_arguments(int argc, char** argv, rdpSettin
 		}
 		CommandLineSwitchDefault(arg)
 		{
-
+			fprintf(stderr, "Unknown argument %s\n", __func__, arg->Name);
+			return COMMAND_LINE_ERROR;
 		}
 
 		CommandLineSwitchEnd(arg)
diff --git a/client/common/compatibility.c b/client/common/compatibility.c
index 048afa599..641bf2f65 100644
--- a/client/common/compatibility.c
+++ b/client/common/compatibility.c
@@ -315,6 +315,7 @@ int freerdp_detect_old_command_line_syntax(int argc, char** argv, int* count)
 	detect_status = 0;
 	flags = COMMAND_LINE_SEPARATOR_SPACE;
 	flags |= COMMAND_LINE_SIGIL_DASH | COMMAND_LINE_SIGIL_DOUBLE_DASH;
+	flags |= COMMAND_LINE_SIGIL_NOT_ESCAPED;
 
 	settings = (rdpSettings*) malloc(sizeof(rdpSettings));
 	ZeroMemory(settings, sizeof(rdpSettings));
@@ -322,6 +323,8 @@ int freerdp_detect_old_command_line_syntax(int argc, char** argv, int* count)
 	CommandLineClearArgumentsA(old_args);
 	status = CommandLineParseArgumentsA(argc, (const char**) argv, old_args, flags, settings,
 			freerdp_client_old_command_line_pre_filter, NULL);
+	if (status < 0)
+		return status;
 
 	arg = old_args;
 
@@ -383,16 +386,12 @@ int freerdp_client_parse_old_command_line_arguments(int argc, char** argv, rdpSe
 	flags = COMMAND_LINE_SEPARATOR_SPACE;
 	flags |= COMMAND_LINE_SIGIL_DASH | COMMAND_LINE_SIGIL_DOUBLE_DASH;
 	flags |= COMMAND_LINE_SIGIL_ENABLE_DISABLE;
+	flags |= COMMAND_LINE_SIGIL_NOT_ESCAPED;
 
 	status = CommandLineParseArgumentsA(argc, (const char**) argv, old_args, flags, settings,
 			freerdp_client_old_command_line_pre_filter, freerdp_client_old_command_line_post_filter);
 
-	if (status == COMMAND_LINE_STATUS_PRINT_HELP)
-	{
-		freerdp_client_print_command_line_help(argc, argv);
-		return COMMAND_LINE_STATUS_PRINT_HELP;
-	}
-	else if (status == COMMAND_LINE_STATUS_PRINT_VERSION)
+	if (status == COMMAND_LINE_STATUS_PRINT_VERSION)
 	{
 		freerdp_client_print_version();
 		return COMMAND_LINE_STATUS_PRINT_VERSION;
@@ -401,6 +400,15 @@ int freerdp_client_parse_old_command_line_arguments(int argc, char** argv, rdpSe
 	{
 		return COMMAND_LINE_STATUS_PRINT;
 	}
+	else if (status < 0)
+	{
+		if (status != COMMAND_LINE_STATUS_PRINT_HELP)
+		{
+
+		}
+		freerdp_client_print_command_line_help(argc, argv);
+		return COMMAND_LINE_STATUS_PRINT_HELP;
+	}
 
 	arg = old_args;
 
diff --git a/winpr/include/winpr/cmdline.h b/winpr/include/winpr/cmdline.h
index bc67d4f52..ca7ae7292 100644
--- a/winpr/include/winpr/cmdline.h
+++ b/winpr/include/winpr/cmdline.h
@@ -53,6 +53,7 @@
 #define COMMAND_LINE_SIGIL_DOUBLE_DASH		0x00000008
 #define COMMAND_LINE_SIGIL_PLUS_MINUS		0x00000010
 #define COMMAND_LINE_SIGIL_ENABLE_DISABLE	0x00000020
+#define COMMAND_LINE_SIGIL_NOT_ESCAPED	0x00000040
 
 #define COMMAND_LINE_SEPARATOR_COLON		0x00000100
 #define COMMAND_LINE_SEPARATOR_EQUAL		0x00000200
diff --git a/winpr/libwinpr/utils/cmdline.c b/winpr/libwinpr/utils/cmdline.c
index 0c998ea4c..1e6c45079 100644
--- a/winpr/libwinpr/utils/cmdline.c
+++ b/winpr/libwinpr/utils/cmdline.c
@@ -53,7 +53,8 @@ int CommandLineParseArgumentsA(int argc, LPCSTR* argv, COMMAND_LINE_ARGUMENT_A*
 	int count;
 	int length;
 	int index;
-	BOOL match;
+	BOOL match, found, argument = FALSE;
+	BOOL notescaped = FALSE;
 	char* sigil;
 	int sigil_length;
 	int sigil_index;
@@ -81,12 +82,12 @@ int CommandLineParseArgumentsA(int argc, LPCSTR* argv, COMMAND_LINE_ARGUMENT_A*
 
 	for (i = 1; i < argc; i++)
 	{
+		BOOL escaped = TRUE;
 		index = i;
 
 		if (preFilter)
 		{
 			count = preFilter(context, i, argc, argv);
-
 			if (count < 0)
 			{
 				status = COMMAND_LINE_ERROR;
@@ -131,12 +132,21 @@ int CommandLineParseArgumentsA(int argc, LPCSTR* argv, COMMAND_LINE_ARGUMENT_A*
 		{
 			sigil_length = 0;
 		}
+		else if (flags & COMMAND_LINE_SIGIL_NOT_ESCAPED)
+		{
+			if (notescaped)
+				return COMMAND_LINE_ERROR; 
+			sigil_length = 0;
+			escaped = FALSE;
+			notescaped = TRUE;
+		}
 		else
 		{
-			continue;
+			return COMMAND_LINE_ERROR;
 		}
-
-		if ((sigil_length > 0) || (flags & COMMAND_LINE_SIGIL_NONE))
+		
+		if ((sigil_length > 0) || (flags & COMMAND_LINE_SIGIL_NONE) ||
+				(flags & COMMAND_LINE_SIGIL_NOT_ESCAPED))
 		{
 			if (length < (sigil_length + 1))
 				return COMMAND_LINE_ERROR_NO_KEYWORD;
@@ -192,6 +202,10 @@ int CommandLineParseArgumentsA(int argc, LPCSTR* argv, COMMAND_LINE_ARGUMENT_A*
 				value_length = 0;
 			}
 
+			if (!escaped)
+				continue;
+
+			found = FALSE;
 			for (j = 0; options[j].Name != NULL; j++)
 			{
 				match = FALSE;
@@ -214,6 +228,7 @@ int CommandLineParseArgumentsA(int argc, LPCSTR* argv, COMMAND_LINE_ARGUMENT_A*
 				if (!match)
 					continue;
 
+				found = match;
 				options[j].Index = index;
 
 				if ((flags & COMMAND_LINE_SEPARATOR_SPACE) && ((i + 1) < argc))
@@ -238,7 +253,13 @@ int CommandLineParseArgumentsA(int argc, LPCSTR* argv, COMMAND_LINE_ARGUMENT_A*
 							value_present = 0;
 					}
 
-					if (value_present)
+					if ((options[j].Flags & COMMAND_LINE_VALUE_REQUIRED) ||
+							(options[j].Flags & COMMAND_LINE_VALUE_OPTIONAL))
+						argument = TRUE;
+					else
+						argument = FALSE;
+					
+					if (value_present && argument)
 					{
 						i++;
 						value_index = 0;
@@ -247,6 +268,14 @@ int CommandLineParseArgumentsA(int argc, LPCSTR* argv, COMMAND_LINE_ARGUMENT_A*
 						value = (char*) &argv[i][value_index];
 						value_length = (length - value_index);
 					}
+					else if (!value_present && (options[j].Flags & COMMAND_LINE_VALUE_OPTIONAL))
+					{
+						value_index = 0;
+						value = NULL;
+						value_length = 0;
+					}
+					else if (!value_present && argument)
+						return COMMAND_LINE_ERROR;
 				}
 
 				if (!(flags & COMMAND_LINE_SEPARATOR_SPACE))
@@ -320,6 +349,9 @@ int CommandLineParseArgumentsA(int argc, LPCSTR* argv, COMMAND_LINE_ARGUMENT_A*
 				else if (options[j].Flags & COMMAND_LINE_PRINT_VERSION)
 						return COMMAND_LINE_STATUS_PRINT_VERSION;
 			}
+			
+			if (!found)
+				return COMMAND_LINE_ERROR_NO_KEYWORD;
 		}
 	}