diff --git a/cpp/open3d/utility/Helper.h b/cpp/open3d/utility/Helper.h
index c1e6a7b1a69..eea200bc56c 100644
--- a/cpp/open3d/utility/Helper.h
+++ b/cpp/open3d/utility/Helper.h
@@ -176,7 +176,7 @@ template <typename... Args>
 inline std::string FastFormatString(const std::string& format, Args... args) {
 #ifdef _WIN32
     return FormatString(format, &args...);
-#endif  // _WIN32
+#else
     char* buffer = nullptr;
     int size_s = asprintf(&buffer, format.c_str(), args...);
     if (size_s == -1) {
@@ -186,6 +186,7 @@ inline std::string FastFormatString(const std::string& format, Args... args) {
                            buffer + size_s);  // no + 1 since we ignore the \0
     std::free(buffer);                        // asprintf calls malloc
     return ret;
+#endif // _WIN32
 };
 
 void Sleep(int milliseconds);