diff --git a/targets/mega65/uart_monitor.c b/targets/mega65/uart_monitor.c
index 6a444d42..993b0106 100644
--- a/targets/mega65/uart_monitor.c
+++ b/targets/mega65/uart_monitor.c
@@ -52,8 +52,8 @@ char umon_write_buffer[UMON_WRITE_BUFFER_SIZE];
 
 #define UNCONNECTED	XS_INVALID_SOCKET
 
-#ifdef XEMU_ARCH_WIN
-#	define PRINTF_SOCK	"%I64d"
+#ifdef XEMU_ARCH_WIN64
+#	define PRINTF_SOCK	"%I64lld"
 #else
 #	define PRINTF_SOCK	"%d"
 #endif
diff --git a/xemu/emutools_basicdefs.h b/xemu/emutools_basicdefs.h
index 8bfac832..6db4f4a1 100644
--- a/xemu/emutools_basicdefs.h
+++ b/xemu/emutools_basicdefs.h
@@ -151,8 +151,8 @@ typedef uint64_t Uint64;
 #	define DIRSEP_CHR	'\\'
 #	define NL		"\r\n"
 #	define NL_LENGTH	2
-#	define PRINTF_LLD	"%I64d"
-#	define PRINTF_LLU	"%I64u"
+#	define PRINTF_LLD	"%I64lld"
+#	define PRINTF_LLU	"%I64llu"
 #	define MKDIR(__n)	mkdir(__n)
 #	define NULL_DEVICE	"NUL:"
 #endif