Intuit has incorporated a "security" protocol to QuickBooks Desktop 2019 to reduce the amount of data corruption that can occur while importing IIF files; nonetheless, this has caused an increase in issues for most individuals trying to import an IIF file.
So, if you're experiencing trouble IIF File Import Quickbooks Desktop. (from a credible source, and you have no reason to suspect the IIF file is the problem), follow these steps:
Once you've saved the IIF file to a convenient location on your computer (like in the Desktop). Go to the top menus of the QuickBooks company file you wish to import it into and select: IIF Files, File, Utilities, Import…
The following box will provide you three options after you select "IIF Files": Import IIF, Cancel, or "Import it for me." "I'll take care of it later." You'll choose the final option, "Import it for me." "I'll take care of it later."
The next step will advise you to create a backup; I ALWAYS RECOMMEND CREATING A BACKUP BEFORE AN IIF IMPORT. So that's something I'd definitely endorse... then select Import IIF from the drop-down menu.
Then explore your computer until you find the IIF file you wish to import, double-click it, and then select Open.
"Your data has been imported," it should say at the end. You can simply click OK.