diff --git a/scripts/build.sh b/scripts/build.sh
index 88437c765..0cad87c6b 100755
--- a/scripts/build.sh
+++ b/scripts/build.sh
@@ -174,26 +174,31 @@ if [ $BUILDMARBLE = 1 ]; then
 	mkdir -p build
 	cd build
 	if [ $PLATFORM = Darwin ] ; then
-		# qmake in PATH?
-		libdir=`qmake -query QT_INSTALL_LIBS`
-		if [ $? -eq 0 ]; then
-			export CMAKE_PREFIX_PATH=$libdir/cmake
-		elif [ -d "$HOME/Qt/5.8" ] ; then
-			export CMAKE_PREFIX_PATH=~/Qt/5.8/clang_64/lib/cmake
-		elif [ -d "$HOME/Qt/5.7" ] ; then
-			export CMAKE_PREFIX_PATH=~/Qt/5.7/clang_64/lib/cmake
-		elif [ -d "$HOME/Qt/5.6" ] ; then
-			export CMAKE_PREFIX_PATH=~/Qt/5.6/clang_64/lib/cmake
-		elif [ -d "$HOME/Qt/5.5" ] ; then
-			export CMAKE_PREFIX_PATH=~/Qt/5.5/clang_64/lib/cmake
-		elif [ -d /usr/local/opt/qt5/lib ] ; then
-			# Homebrew location for qt5 package
-			export CMAKE_PREFIX_PATH=/usr/local/opt/qt5/lib/cmake
-		else
-			echo "cannot find Qt 5.5 or 5.6 in ~/Qt"
-			exit 1
+		if [ -z "$CMAKE_PREFIX_PATH" ] ; then
+			# qmake in PATH?
+			libdir=`qmake -query QT_INSTALL_LIBS`
+			if [ $? -eq 0 ]; then
+				export CMAKE_PREFIX_PATH=$libdir/cmake
+			elif [ -d "$HOME/Qt/5.9.1" ] ; then
+				export CMAKE_PREFIX_PATH=~/Qt/5.9.1/clang_64/lib/cmake
+			elif [ -d "$HOME/Qt/5.9" ] ; then
+				export CMAKE_PREFIX_PATH=~/Qt/5.9/clang_64/lib/cmake
+			elif [ -d "$HOME/Qt/5.8" ] ; then
+				export CMAKE_PREFIX_PATH=~/Qt/5.8/clang_64/lib/cmake
+			elif [ -d "$HOME/Qt/5.7" ] ; then
+				export CMAKE_PREFIX_PATH=~/Qt/5.7/clang_64/lib/cmake
+			elif [ -d "$HOME/Qt/5.6" ] ; then
+				export CMAKE_PREFIX_PATH=~/Qt/5.6/clang_64/lib/cmake
+			elif [ -d "$HOME/Qt/5.5" ] ; then
+				export CMAKE_PREFIX_PATH=~/Qt/5.5/clang_64/lib/cmake
+			elif [ -d /usr/local/opt/qt5/lib ] ; then
+				# Homebrew location for qt5 package
+				export CMAKE_PREFIX_PATH=/usr/local/opt/qt5/lib/cmake
+			else
+				echo "cannot find Qt 5.5 or newer in ~/Qt"
+				exit 1
+			fi
 		fi
-
 	fi
 
 	cmake -DCMAKE_BUILD_TYPE=Release -DQTONLY=TRUE -DQT5BUILD=ON \