diff --git a/system-dependencies.sh b/system-dependencies.sh
index fa871368c37b..72ab5b6bb986 100755
--- a/system-dependencies.sh
+++ b/system-dependencies.sh
@@ -198,10 +198,16 @@ function check_specific_xcode () {
 	local XCODE_DEVELOPER_ROOT=`grep XCODE$1_DEVELOPER_ROOT= Make.config | sed 's/.*=//'`
 	local XCODE_VERSION=`grep XCODE$1_VERSION= Make.config | sed 's/.*=//'`
 	local XCODE_ROOT=$(dirname `dirname $XCODE_DEVELOPER_ROOT`)
+	local ENABLE_XAMARIN=$(grep -s ^ENABLE_XAMARIN= Make.config.local configure.inc | sed 's/.*=//')
 	
 	if ! test -d $XCODE_DEVELOPER_ROOT; then
 		if ! test -z $PROVISION_XCODE; then
-			install_specific_xcode $1
+			if ! test -z $ENABLE_XAMARIN; then
+				install_specific_xcode $1
+			else
+				fail "Automatic provisioning of Xcode is only supported for provisioning internal build bots."
+				fail "Please download and install Xcode $XCODE_VERSION here: https://developer.apple.com/downloads/index.action?name=Xcode"
+			fi
 		else
 			fail "You must install Xcode ($XCODE_VERSION) in $XCODE_ROOT. You can download Xcode $XCODE_VERSION here: https://developer.apple.com/downloads/index.action?name=Xcode"
 		fi