diff --git a/app/src/protyle/wysiwyg/transaction.ts b/app/src/protyle/wysiwyg/transaction.ts
index b5c798492..292a0c9dc 100644
--- a/app/src/protyle/wysiwyg/transaction.ts
+++ b/app/src/protyle/wysiwyg/transaction.ts
@@ -527,7 +527,7 @@ export const onTransaction = (protyle: IProtyle, operation: IOperation, isUndo:
                     window.siyuan.mobile.editor.protyle.background.render(window.siyuan.mobile.editor.protyle.background.ial, window.siyuan.mobile.editor.protyle.block.rootID);
                 }
                 /// #else
-                if (protyle.background.ial.icon !== data.new.icon) {
+                if (protyle.background && protyle.background.ial.icon !== data.new.icon) {
                     protyle.background.ial.icon = data.new.icon;
                     protyle.background.render(protyle.background.ial, protyle.block.rootID);
                     protyle.model?.parent.setDocIcon(data.new.icon);