1 files changed, 3 insertions, 1 deletions
diff --git a/src/nvim/diff.c b/src/nvim/diff.c
index cc0f3b2629..dd489c18e9 100644
--- a/src/nvim/diff.c
+++ b/src/nvim/diff.c
@@ -1161,7 +1161,9 @@ void ex_diffoff(exarg_T *eap)
         }
 
         free_string_option(wp->w_p_fdm);
-        wp->w_p_fdm = vim_strsave(wp->w_p_fdm_save);
+        wp->w_p_fdm = vim_strsave(*wp->w_p_fdm_save
+                                  ? wp->w_p_fdm_save
+                                  : (char_u*)"manual");
         if (wp->w_p_fdc == diff_foldcolumn) {
           wp->w_p_fdc = wp->w_p_fdc_save;
         }