Welcome to the Community forum, @mateen_hyd.

If you’re based in Australia, it’s important to note that the QuickBooks Desktop migrator tool is not available in this region. Instead, you’ll need to convert a QBX file to a QBW file in QuickBooks Desktop (QBDT) first, then manually import specific data, such as lists, into your QuickBooks Online company.

Here's how to convert QBX file to a QBW file:

1. On your QBDT, click the File menu in the top-left corner.
2. Select Accountant's Copy, then choose Convert Accountant's Copy to Company File.
3. Follow the prompts and save the file as a QBW file on your computer.

After that, export the data from QuickBooks Desktop:

1. Open the QBW file in QuickBooks Desktop.
2. Click the Lists or Reports menu depending on the data type you want to export.
3. Select the Lists or Reports you need.
4. Once the data is displayed, click the Excel button at the top of the report.
5. Export the data as a CSV file and save it on your computer for import into QuickBooks Online.

Once done, import the lists into QBO:

1. Log into your QBO account.
2. Click the Gear icon in the upper-right corner.
3. Select Import Data from the menu.
4. Choose the type of data you want to import.
5. Click Browse, select the exported CSV file, and upload it.
6. Follow the on-screen instructions to map fields and complete the import.
7. Repeat these steps for other list types as needed.

Feel free to leave a reply below for any additional queries or concerns. We’ll be around to help.

@mateen_hyd 

Where is your client located? US or Canada?