--- a/build.vc15/lib_mpfr/lib_mpfr.vcxproj
+++ a/build.vc15/lib_mpfr/lib_mpfr.vcxproj
@@ -25 +25 @@
-    <WindowsTargetPlatformVersion>10.0.17134.0</WindowsTargetPlatformVersion>
+    <WindowsTargetPlatformVersion>sdk</WindowsTargetPlatformVersion>