QuickBooks 2019/Enterprise 19.0 has an improved .IIF functionality which not only shows you the number of items successfully imported or failed, but also provides you with a new .IIF file of the failed transactions along with messaging about why they failed. Not only does this make it easier for you, it also eliminates the possibility of importing bad data into your file.
Go to File > Utilities > Import > IIF Files.
Select Import IIF, browse to your file and select OK.
If your file was imported correctly, you’ll see a message that shows the number of list/transactions items successfully imported.
If not, a message will appear showing both the number of successful as well as failed list/transactions items. QuickBooks will also create a new IIF file for the failed records.
You can either:
Review now to fix and re-import the file.
Open in folder to see where the file is saved.
Close the import window.
To review the errors in your file:
Select Review now.
Look for ERROR to see what the problem(s) with the file is.
Correct the errors and Save. If asked if you want to keep the file type, select Yes.
Close the File not imported window.
Import the new, corrected .IIF file.
Note: Intuit does not offer assisted technical support for creating or importing .IIF files