diff --git a/Source/Core/Common/SysConf.h b/Source/Core/Common/SysConf.h
index 9600e725bd..6b25dc058d 100644
--- a/Source/Core/Common/SysConf.h
+++ b/Source/Core/Common/SysConf.h
@@ -17,7 +17,7 @@
 class SysConf final
 {
 public:
-  SysConf(Common::FromWhichRoot root_type);
+  explicit SysConf(Common::FromWhichRoot root_type);
   ~SysConf();
 
   void Clear();