diff --git a/src/quickfix.c b/src/quickfix.c
index 99b0169..f8ff776 100644
--- a/src/quickfix.c
+++ b/src/quickfix.c
@@ -6022,7 +6022,7 @@
     static int
 existing_swapfile(buf_T *buf)
 {
-    if (buf->b_ml.ml_mfp != NULL)
+    if (buf->b_ml.ml_mfp != NULL && buf->b_ml.ml_mfp->mf_fname != NULL)
     {
 	char_u *fname = buf->b_ml.ml_mfp->mf_fname;
 	size_t len = STRLEN(fname);