diff --git a/src/OSSupport/Event.cpp b/src/OSSupport/Event.cpp
index 6b8fccde2..72bce4c3c 100644
--- a/src/OSSupport/Event.cpp
+++ b/src/OSSupport/Event.cpp
@@ -18,7 +18,7 @@ cEvent::cEvent(void)
 	m_Event = CreateEvent(NULL, FALSE, FALSE, NULL);
 	if (m_Event == NULL)
 	{
-		LOGERROR("cEvent: cannot create event, GLE = %d. Aborting server.", GetLastError());
+		LOGERROR("cEvent: cannot create event, GLE = %u. Aborting server.", (unsigned)GetLastError());
 		abort();
 	}
 #else  // *nix
@@ -86,7 +86,7 @@ void cEvent::Wait(void)
 		DWORD res = WaitForSingleObject(m_Event, INFINITE);
 		if (res != WAIT_OBJECT_0)
 		{
-			LOGWARN("cEvent: waiting for the event failed: %d, GLE = %d. Continuing, but server may be unstable.", res, GetLastError());
+			LOGWARN("cEvent: waiting for the event failed: %u, GLE = %u. Continuing, but server may be unstable.", (unsigned)res, (unsigned)GetLastError());
 		}
 	#else
 		int res = sem_wait(m_Event);
@@ -107,7 +107,7 @@ void cEvent::Set(void)
 	#ifdef _WIN32
 		if (!SetEvent(m_Event))
 		{
-			LOGWARN("cEvent: Could not set cEvent: GLE = %d", GetLastError());
+			LOGWARN("cEvent: Could not set cEvent: GLE = %u", (unsigned)GetLastError());
 		}
 	#else
 		int res = sem_post(m_Event);
diff --git a/src/OSSupport/IsThread.cpp b/src/OSSupport/IsThread.cpp
index 67f336c97..1a436623a 100644
--- a/src/OSSupport/IsThread.cpp
+++ b/src/OSSupport/IsThread.cpp
@@ -90,7 +90,7 @@ bool cIsThread::Start(void)
 		m_Handle = CreateThread(NULL, 0, thrExecute, this, CREATE_SUSPENDED, &m_ThreadID);
 		if (m_Handle == NULL)
 		{
-			LOGERROR("ERROR: Could not create thread \"%s\", GLE = %d!", m_ThreadName.c_str(), GetLastError());
+			LOGERROR("ERROR: Could not create thread \"%s\", GLE = %u!", m_ThreadName.c_str(), (unsigned)GetLastError());
 			return false;
 		}
 		ResumeThread(m_Handle);