1 files changed, 4 insertions, 1 deletions
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index d426fb2064..5ab1e0ebbe 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -14854,7 +14854,10 @@ static void set_buffer_lines(buf_T *buf, linenr_T lnum, typval_T *lines,
   buf_T       *curbuf_save;
   int         is_curbuf = buf == curbuf;
 
-  if (buf == NULL || buf->b_ml.ml_mfp == NULL || lnum < 1) {
+  // When using the current buffer ml_mfp will be set if needed.  Useful when
+  // setline() is used on startup.  For other buffers the buffer must be
+  // loaded.
+  if (buf == NULL || (!is_curbuf && buf->b_ml.ml_mfp == NULL) || lnum < 1) {
     rettv->vval.v_number = 1;  // FAIL
     return;
   }