diff --git a/deps/graph-parser/src/logseq/graph_parser/block.cljc b/deps/graph-parser/src/logseq/graph_parser/block.cljc
index 8b2a24035..d03c51bcc 100644
--- a/deps/graph-parser/src/logseq/graph_parser/block.cljc
+++ b/deps/graph-parser/src/logseq/graph_parser/block.cljc
@@ -431,7 +431,8 @@
   (or (when-let [custom-id (or (get-in properties [:properties :custom-id])
                                (get-in properties [:properties :custom_id])
                                (get-in properties [:properties :id]))]
-        (let [custom-id (and (string? custom-id) (string/trim custom-id))]
+        ;; guard against non-string custom-ids
+        (when-let [custom-id (and (string? custom-id) (string/trim custom-id))]
           (some-> custom-id parse-uuid)))
       (d/squuid)))