diff --git a/src/filesys.cpp b/src/filesys.cpp
index 5fdc97634..501f9ad6c 100644
--- a/src/filesys.cpp
+++ b/src/filesys.cpp
@@ -693,13 +693,22 @@ bool safeWriteToFile(const std::string &path, const std::string &content)
 	os.flush();
 	os.close();
 	if (os.fail()) {
+		// Remove the temporary file because writing it failed and it's useless.
 		remove(tmp_file.c_str());
 		return false;
 	}
 
-	// Copy file
+	// Move the finished temporary file over the real file
+#ifdef _WIN32
+	// On POSIX compliant systems rename() is specified to be able to swap the
+	// file in place of the destination file, making this a truly error-proof
+	// transaction.
+	// However, on Windows, the target file has to be removed first.
 	remove(path.c_str());
+#endif
 	if(rename(tmp_file.c_str(), path.c_str())) {
+		// Remove the temporary file because moving it over the target file
+		// failed.
 		remove(tmp_file.c_str());
 		return false;
 	} else {