diff --git a/Build.md b/Build.md
index 77f6cbe..41e7963 100644
--- a/Build.md
+++ b/Build.md
@@ -212,6 +212,8 @@ exec /path/to/ccls/Release/ccls -init='{"clang":{"extraArgs":["-isystem", "/Appl
 
 With clang < 8, `"-isystem", "/Library/Developer/CommandLineTools/usr/include/c++/v1"` is also needed (https://github.com/MaskRay/ccls/issues/191#issuecomment-453809905)
 
+With most recent MacOSs(e.g. Catalina 10.15.2), one more clang.extraArgs is needed to make ccls work properly (https://github.com/MaskRay/ccls/issues/512#issuecomment-545575369)
+
 ### FreeBSD
 
 * [devel/ccls](https://www.freshports.org/devel/ccls)