diff --git a/util/buildbot/buildwin32.sh b/util/buildbot/buildwin32.sh
index 8711cae42..e900a53d3 100755
--- a/util/buildbot/buildwin32.sh
+++ b/util/buildbot/buildwin32.sh
@@ -71,7 +71,7 @@ cd $libdir
 
 # Get minetest
 cd $builddir
-if [ -d $EXISTING_MINETEST_DIR ]; then
+if [ ! "x$EXISTING_MINETEST_DIR" = "x" ]; then
 	ln -s $EXISTING_MINETEST_DIR minetest
 else
 	[ -d minetest ] && (cd minetest && git pull) || (git clone https://github.com/minetest/minetest)
diff --git a/util/buildbot/buildwin64.sh b/util/buildbot/buildwin64.sh
index 678d9e952..b951ff498 100755
--- a/util/buildbot/buildwin64.sh
+++ b/util/buildbot/buildwin64.sh
@@ -66,7 +66,7 @@ cd $libdir
 
 # Get minetest
 cd $builddir
-if [ -d $EXISTING_MINETEST_DIR ]; then
+if [ ! "x$EXISTING_MINETEST_DIR" = "x" ]; then
 	ln -s $EXISTING_MINETEST_DIR minetest
 else
 	[ -d minetest ] && (cd minetest && git pull) || (git clone https://github.com/minetest/minetest)