If you find yourself having issues importing an IIF file into Quick Books try checking to see if one of your imported items has a hyphen (-) in its name. Removing the hyphen may fix the issue.
UPDATE 2015-06-15: IIF imports can also crash because of field length limits being exceeded. I’ve encountered scenarios where Quick Books:
- will take longer data then the fields max length but will not be able to display it all in app (seen in invoice numbers)
- will take longer data then the fields max length but truncates it in system. This can cause duplicate items to be created
- crashes immediately
So don’t forget to check the fields max length: Character limitations for fields in QuickBooks