diff --git a/cmdline/mingw.c b/cmdline/mingw.c
index 64e35ec5..747cae9f 100644
--- a/cmdline/mingw.c
+++ b/cmdline/mingw.c
@@ -177,6 +177,9 @@ void os_init(int opt)
 	}
 
 	exedir_init();
+
+	/* set LC_ALL=C to make smartctl ignoring the locale when printing info */
+	_wputenv_s(L"LC_ALL", L"C");
 }
 
 void os_done(void)
diff --git a/cmdline/unix.c b/cmdline/unix.c
index 7343da0e..8cfc2601 100644
--- a/cmdline/unix.c
+++ b/cmdline/unix.c
@@ -2404,6 +2404,9 @@ void os_init(int opt)
 	}
 #endif
 
+	/* set LC_ALL=C to make smartctl ignoring the locale when printing info */
+	setenv("LC_ALL", "C", 1);
+
 	(void)opt;
 }