diff --git a/recovery-refresh.cpp b/recovery-refresh.cpp
index 333367e..b75c915 100644
--- a/recovery-refresh.cpp
+++ b/recovery-refresh.cpp
@@ -76,7 +76,7 @@
     }
 
     std::string name(filename);
-    size_t dot = name.find_last_of(".");
+    size_t dot = name.find_last_of('.');
     std::string sub = name.substr(0, dot);
 
     if (!strstr(LAST_KMSG_FILE, sub.c_str()) &&