If you already have QuickBooks installed on your systems and IIF files are still not opened properly, check if you have the latest version of the software. Check the version of QuickBooks and update if needed website and download from their official repositories. If you want to download QuickBooks installer in the most secured manner, we suggest you visit Intuit Inc. The full list of programs grouped by operating systems can be found above. This issue can be addressed by downloading and installing QuickBooks or different compatible program, such as Microsoft Excel, Windows Notepad, Total Office Manager. The main and most frequent cause precluding users form opening IIF files is that no program that can handle IIF files is installed on user’s system. The following is a list of guidelines that will help you identify and solve file-related problems. In most cases they can be addressed swiftly and effectively without assistance from a specialist. On the bright side, the most encountered issues pertaining to Intuit Interchange Format files aren’t complex. There can be multiple causes why you have problems with opening IIF files on given system.