I lost possibility to delete attached file. Because I can see the remove option (X) on the attachment as usual.

Hello there, @Iryna1.

I'm here to help ensure you can remove the attached file.

One of the possible reasons why the X option to remove the attachment is missing is that the browser you're using had a data issue. To verify, let's log in to your QBO account using a private browser. To do so, press this shortcut key on your keyboard:

• Google Chrome: Ctrl + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Safari: Command + Option + P

Once logged in, go back and remove the attachment again to double-check. If this works, it means that you need to clear the browser's cache so the system can start fresh. If you get the same result while using a private browser, I recommend switching to a different one. 

Just in case you want to review all your sales and expense transactions in the future, you can run and customize some reports in QBO. For more guidance, feel free to read this article: Common custom reports in QuickBooks Online.

You're always welcome to post again, @Iryna1. Don't hesitate to click the Reply button below if you need further assistance removing attachments. Have a good one.