diff --git a/src/nvim/memline.c b/src/nvim/memline.c
index f7f272f8dd..a0900faeab 100644
--- a/src/nvim/memline.c
+++ b/src/nvim/memline.c
@@ -510,6 +510,11 @@ void ml_open_file(buf_T *buf)
     // and creating it, another Vim creates the file.  In that case the
     // creation will fail and we will use another directory.
     char *fname = findswapname(buf, &dirp, NULL, &found_existing_dir);
+    // autocmd may have freed mfp, grr!
+    if (buf->b_ml.ml_mfp != mfp) {
+      xfree(fname);
+      return;
+    }
     if (dirp == NULL) {
       break;        // out of memory
     }