Let's make sure you can import your .IIF file successfully, bexpress.
First, let's do the Verify and Rebuild process to get rid of any data-integrity issues. This will help us fix your company file. You can use this article for reference: Verify and Rebuild Data in QuickBooks Desktop.
Then, you can import the .IIF file again. Otherwise, you can follow the steps in this article on how you can fix the .IIF file: Import IIF Import in QuickBooks 2019.
If you need more help with this, additional details (such as screenshots or error messages/codes) would be much appreciated. I'll be around!
