Let me help you find ways how to manage importing huge files in QuickBooks Desktop, Jmorrisls.

Before proceeding, to convert all your data files to QuickBooks Online, we will utilize the condense data tool to reduce the Total Target below 750K, and then convert the condensed file to QBO Advanced.

However, since we're unable to suggest third-party apps, I encourage you to visit our Desktop Marketplace so you can choose an application that can manage to import a large amount of data from your QuickBooks Desktop to QuickBooks Online Version.

With that, I'll route it to the QuickBooks Desktop App Center. Then, pick an app in the categories section or find them in the search bar. You can also visit this link for additional references: QuickBooks Desktop App Center.

On the other hand, you'll want to create a backup company file and restore them at any time. Refer to this page for the complete instructions: Back up your QuickBooks Desktop company file.

Please let me know if you require assistance importing data from your QuickBooks Desktop (QBDT) account. I'm still available 24/7 on the clock. Have a great day.