diff --git a/AdaptiveBrightness/monitor_control_win.cpp b/AdaptiveBrightness/monitor_control_win.cpp
index 4e8b012..e64e0b6 100644
--- a/AdaptiveBrightness/monitor_control_win.cpp
+++ b/AdaptiveBrightness/monitor_control_win.cpp
@@ -39,7 +39,7 @@ static QString getLastErrorString()
 {
     DWORD lastErrorId = GetLastError();
 
-    TCHAR* msgBuf;
+    TCHAR* msgBuf = nullptr;
     const auto formatFlags = FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS;
 
     if(FormatMessage(formatFlags, nullptr, lastErrorId, 0, reinterpret_cast<LPTSTR>(&msgBuf), 0, nullptr) == 0) {