diff --git a/src/lib/openjp2/event.c b/src/lib/openjp2/event.c
index 3251849d..aad9d76c 100644
--- a/src/lib/openjp2/event.c
+++ b/src/lib/openjp2/event.c
@@ -121,16 +121,14 @@ OPJ_BOOL opj_event_msg(opj_event_mgr_t* p_event_mgr, OPJ_INT32 event_type,
 
     if ((fmt != 00) && (p_event_mgr != 00)) {
         va_list arg;
-        size_t str_length/*, i, j*/; /* UniPG */
         char message[OPJ_MSG_SIZE];
         memset(message, 0, OPJ_MSG_SIZE);
         /* initialize the optional parameter list */
         va_start(arg, fmt);
-        /* check the length of the format string */
-        str_length = (strlen(fmt) > OPJ_MSG_SIZE) ? OPJ_MSG_SIZE : strlen(fmt);
-        (void)str_length;
         /* parse the format string and put the result in 'message' */
-        vsnprintf(message, OPJ_MSG_SIZE, fmt, arg); /* UniPG */
+        vsnprintf(message, OPJ_MSG_SIZE, fmt, arg);
+        /* force zero termination for Windows _vsnprintf() of old MSVC */
+        message[OPJ_MSG_SIZE - 1] = '\0';
         /* deinitialize the optional parameter list */
         va_end(arg);