diff --git a/lisp/gnus/nnimap.el b/lisp/gnus/nnimap.el
index 67c5db1e04..5f8e9d5ec0 100644
--- a/lisp/gnus/nnimap.el
+++ b/lisp/gnus/nnimap.el
@@ -1702,18 +1702,19 @@ nnimap-update-qresync-info
 	     (cdr (or (assoc (caddr type) flags) ; %Flagged
 		      (assoc (intern (cadr type) obarray) flags)
 		      (assoc (cadr type) flags))))) ; "\Flagged"
-	(setq marks (delq ticks marks))
-	(pop ticks)
-	;; Add the new marks we got.
-	(setq ticks (gnus-add-to-range ticks new-marks))
-	;; Remove the marks from messages that don't have them.
-	(setq ticks (gnus-remove-from-range
-		     ticks
-		     (gnus-compress-sequence
-		      (gnus-sorted-complement existing new-marks))))
-	(when ticks
-	  (push (cons (car type) ticks) marks)))
-      (gnus-info-set-marks info marks t))
+	(when new-marks
+	  (setq marks (delq ticks marks))
+	  (pop ticks)
+	  ;; Add the new marks we got.
+	  (setq ticks (gnus-add-to-range ticks new-marks))
+	  ;; Remove the marks from messages that don't have them.
+	  (setq ticks (gnus-remove-from-range
+		       ticks
+		       (gnus-compress-sequence
+			(gnus-sorted-complement existing new-marks))))
+	  (when ticks
+	    (push (cons (car type) ticks) marks))
+	  (gnus-info-set-marks info marks t))))
     ;; Add vanished to the list of unexisting articles.
     (when vanished
       (let* ((old-unexists (assq 'unexist marks))