Hi there, @scottrussell. 

Thank you for choosing QuickBooks as your accounting tools. I'm here to share additional information about QuickBooks Attached Documents. 

Transferring back up attachments in QuickBooks Desktop is unavailable. You'll need to manually backup of the “Attach” folder which can be found in the same location as your QuickBooks company file. For more information about this process, please refer to this article: QuickBooks Attached Documents: FAQs and common issues.  

I know how important it is to have this option to eliminate time-consuming. Rest assured, our developer's team is working hard to develop the best features to fit the needs of our customers. 

I've also attached this article to check the limitation on the export from QuickBooks Desktop to QuickBooks Online: What to expect when you switch from QuickBooks Desktop to QuickBooks Online. 

Please don't hesitate to reach back out to us if there's anything else you need. We're always here to help. Have a good one!