diff --git a/sbin/tunefs/tunefs.8 b/sbin/tunefs/tunefs.8
index d68211d64c83..e7e4655f1a2c 100644
--- a/sbin/tunefs/tunefs.8
+++ b/sbin/tunefs/tunefs.8
@@ -120,6 +120,25 @@ obtained in the
 .Xr dumpfs 8
 manual page.
 .El
+.Sh ERRORS
+If
+.Nm
+.Fl n
+is run to enable/disable soft update on an unmounted file system
+after booting single-user then
+.Nm
+will output the warning
+.Pp
+reload\&: Invalid argument
+.Pp
+preceded by the raw device name. This occurs because the filesystem
+is not currently mounted read-only.
+.Nm
+is trying to reload the incore (r*) device, but it was never loaded
+to begin with. When you boot single user, only
+.Dq /
+is mounted, so all other filesystems will give you that warning.
+It is completely harmless.
 .Sh SEE ALSO
 .Xr fs 5 ,
 .Xr dumpfs 8 ,