Hi there, @ellegrace.
When converting your QuickBooks Desktop (QBDT) data to QuickBooks Online (QBO), you'll have to make sure that the file is less than 350,000 targets. This way, you can successfully convert your QBDT file to QBO.
Since your file has 1.4M targets, the only way we can consider right now is to condense the data to lower down the targets. I understand that the owner wants to keep the history of the transactions for several years.
Once you're ready to condense the data, please follow the detailed steps below:
- In your QBDT account, go to the File menu, then select Utilities and select Condense Data.
- Click Yes to the message Budget data may be moved during cleanup. Do you want to continue anyway?
- Select Transactions before a specific date in the Condense Data window.
- In the Date field, select a date. QuickBooks will remove closed transactions on or before the date you choose.
- Click Next.
- Choose a method to summarize the transactions you're removing and select Next.
- Click Begin Condense.
Here's an article you can read for more details: Condense your QuickBooks Desktop file for import to QuickBooks Online.
Once done, you can now proceed with moving your QBDT file to QBO. For more guidance, feel free to check out this article: Move your QuickBooks Desktop file to QuickBooks Online.
I'm also adding this article to know what data doesn't convert when you migrate from QBDT to QBO: What to expect when you switch from QuickBooks Desktop to QuickBooks Online.
Please keep in touch if there's anything else I can do to help you succeed with QuickBooks. I've got your back. Have a great day!
