diff --git a/src/athena/FileReaderWin32.cpp b/src/athena/FileReaderWin32.cpp
index 5299559..91bcb65 100644
--- a/src/athena/FileReaderWin32.cpp
+++ b/src/athena/FileReaderWin32.cpp
@@ -42,7 +42,7 @@ void FileReader::open() {
     m_fileHandle = 0;
     std::string _filename = filename();
     if (m_globalErr)
-      atError("File not found '{}'") _filename);
+      atError("File not found '{}'", _filename);
     setError();
     return;
   }
diff --git a/src/athena/FileWriterWin32.cpp b/src/athena/FileWriterWin32.cpp
index de71d68..4755d01 100644
--- a/src/athena/FileWriterWin32.cpp
+++ b/src/athena/FileWriterWin32.cpp
@@ -48,8 +48,10 @@ void FileWriter::open(bool overwrite) {
 
   if (m_fileHandle == INVALID_HANDLE_VALUE) {
     m_fileHandle = 0;
-    if (m_globalErr)
-      atError("Unable to open file '{}'", filename());
+    if (m_globalErr) {
+      auto _filename = filename();
+      atError("Unable to open file '{}'", _filename);
+    }
     setError();
     return;
   }