Hi Lisa,

Thank you for trying in an Incognito browser. I would like to add more information.

QuickBooks uses your Adobe Reader or your browser's PDF viewer, so please be sure to update them to get the components QuickBooks need to attach your files. For more information, please refer to JenoP's answer above.

On the other hand, you can refer to your browser's manual or ask for help from their Support if you don't know how to update its PDF viewer or the browser itself. Please note that an update may include changes to your interface, browser security, and other functions, not just to your PDF viewer.

By the way, this error may exist in QuickBooks Desktop. I know this is a QuickBooks Online thread, but in case you also have a desktop product, you can refer to this article: Troubleshoot PDF and Print problems with QuickBooks Desktop.

Feel free to reach back out if you need more help with attaching your files.