diff --git a/ChangeLog b/ChangeLog
index 0ff62943..710603e8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2026-04-24  Mats Lidell  <matsl@gnu.org>
+
+* test/hyrolo-tests.el (hyrolo-tests--add--error-cases): New test.
+    (hyrolo-tests--add-items-at-multiple-levels):
+    (hyrolo-tests--add-items-interactive): Fix quotes in docstring.
+
+* hyrolo.el (hyrolo-add): Handle not existing file error case.
+
 2026-04-21  Mats Lidell  <matsl@gnu.org>
 
 * Makefile (COVERAGE_TESTSPEC): Use test= for specifying the test selector
diff --git a/hyrolo.el b/hyrolo.el
index 6ccca4e4..9e07a030 100644
--- a/hyrolo.el
+++ b/hyrolo.el
@@ -401,7 +401,7 @@ entry which begins with the parent string."
 				(mapcar #'list (hyrolo-get-file-list)))))
   (unless file
     (setq file (car (hyrolo-get-file-list))))
-  (cond ((and file (or (not (stringp file)) (string-equal file "")))
+  (cond ((and file (or (not (stringp file)) (string-equal file "") (not (file-exists-p file))))
 	 (error "(hyrolo-add): Invalid file: `%s'" file))
 	((and (file-exists-p file) (not (file-readable-p file)))
 	 (error "(hyrolo-add): File not readable: `%s'" file))
diff --git a/test/hyrolo-tests.el b/test/hyrolo-tests.el
index ae0ff7b7..8dacb56d 100644
--- a/test/hyrolo-tests.el
+++ b/test/hyrolo-tests.el
@@ -28,8 +28,31 @@
 
 (declare-function hy-test-helpers:consume-input-events "hy-test-helpers")
 
+(ert-deftest hyrolo-tests--add--error-cases ()
+  "Verify `hyrolo-add' error cases."
+  (defvar hyrolo-file)
+  (let ((hyrolo-file (make-temp-file "hypb" nil ".otl")))
+    (unwind-protect
+        (let ((hyrolo-file-list (list hyrolo-file)))
+          (should-error (hyrolo-add ""))
+          (should-error (hyrolo-add 'symbol))
+          (should-error (hyrolo-add "a" ""))
+          (should-error (hyrolo-add "a" 'symbol))
+          (should-error (hyrolo-add "a/b/c"))
+          ;; File does not exist
+          (should-error (hyrolo-add "a" "/tmp/file-does-not-exist"))
+          ;; File not writable
+          (with-mock
+            (mock (file-writable-p hyrolo-file) => nil)
+            (should-error (hyrolo-add "a")))
+          ;; File not readable
+          (with-mock
+            (mock (file-readable-p hyrolo-file) => nil)
+            (should-error (hyrolo-add "a"))))
+      (hy-delete-file-and-buffer hyrolo-file))))
+
 (ert-deftest hyrolo-tests--add-items-at-multiple-levels ()
-  "`hyrolo-add` can add items at different levels."
+  "`hyrolo-add' can add items at different levels."
   (let ((hyrolo-file (make-temp-file "hypb" nil ".otl")))
     (unwind-protect
         (let ((hyrolo-file-list (list hyrolo-file)))
@@ -45,7 +68,7 @@
       (hy-delete-file-and-buffer hyrolo-file))))
 
 (ert-deftest hyrolo-tests--add-items-interactive ()
-  "`hyrolo-add` can add items when called interactively."
+  "`hyrolo-add' can add items when called interactively."
   (let ((hyrolo-file (make-temp-file "hypb" nil ".otl")))
     (unwind-protect
         (let ((hyrolo-file-list (list hyrolo-file)))