diff --git a/vvp/vpi_mcd.cc b/vvp/vpi_mcd.cc
index 2406cd7a0..8a776864d 100644
--- a/vvp/vpi_mcd.cc
+++ b/vvp/vpi_mcd.cc
@@ -180,6 +180,8 @@ vpi_mcd_vprintf(PLI_UINT32 mcd, const char*fmt, va_list ap)
       char *buf_ptr = buffer;
       int rc = 0;
       bool need_free = false;
+      va_list save_ap;
+      va_copy(save_ap, ap);
 
       if (!IS_MCD(mcd)) return 0;
 
@@ -206,9 +208,9 @@ vpi_mcd_vprintf(PLI_UINT32 mcd, const char*fmt, va_list ap)
 	    buf_ptr = (char *)malloc(rc + 1);
 	    need_free = true;
 #ifdef __MINGW32__
-	    rc = _vsnprintf(buf_ptr, rc+1, fmt, ap);
+	    rc = _vsnprintf(buf_ptr, rc+1, fmt, save_ap);
 #else
-	    rc = vsnprintf(buf_ptr, rc+1, fmt, ap);
+	    rc = vsnprintf(buf_ptr, rc+1, fmt, save_ap);
 #endif
       }