diff --git a/Makefile.libretro b/Makefile.libretro
index 069f0ce..322c13d 100644
--- a/Makefile.libretro
+++ b/Makefile.libretro
@@ -319,9 +319,15 @@ else ifeq ($(platform), windows_msvc2017_x64)
 	VsInstallCommunity = $(ProgramFiles86)/Microsoft Visual Studio/2017/Community
 
 	VsInstallRoot ?= $(shell if [ -d "$(VsInstallBuildTools)" ]; then echo "$(VsInstallBuildTools)"; fi)
-	VsInstallRoot ?= $(shell if [ -d "$(VsInstallEnterprise)" ]; then echo "$(VsInstallEnterprise)"; fi)
-	VsInstallRoot ?= $(shell if [ -d "$(VsInstallProfessional)" ]; then echo "$(VsInstallProfessional)"; fi)
-	VsInstallRoot ?= $(shell if [ -d "$(VsInstallCommunity)" ]; then echo "$(VsInstallCommunity)"; fi)
+	ifeq ($(VsInstallRoot), )
+		VsInstallRoot = $(shell if [ -d "$(VsInstallEnterprise)" ]; then echo "$(VsInstallEnterprise)"; fi)
+	endif
+	ifeq ($(VsInstallRoot), )
+		VsInstallRoot = $(shell if [ -d "$(VsInstallProfessional)" ]; then echo "$(VsInstallProfessional)"; fi)
+	endif
+	ifeq ($(VsInstallRoot), )
+		VsInstallRoot = $(shell if [ -d "$(VsInstallCommunity)" ]; then echo "$(VsInstallCommunity)"; fi)
+	endif
 	VsInstallRoot := $(VsInstallRoot)
 
 	VcCompilerToolsVer := $(shell cat "$(VsInstallRoot)/VC/Auxiliary/Build/Microsoft.VCToolsVersion.default.txt" | grep -o '[0-9\.]*')