IIF file - Error message says: Problem: You are trying to open a QuickBooks file. Only QuickBooks company files can be opened this way? HELP!! I need to work.

It sounds like you're double-clicking the IIF file in order to open it.  That won't work.

If you are trying to import the file into your QB file, pick Import IIF file... from the File | Utilities | Import file.

I get the same message.  Not double clicking.  

It wants to use Quickbooks Launcher to open the file.  What file should be used to open the IIF file?  Don't say Excel as that is an xls .

Thank you for posting here in the Community, @Kyle57.

I'd be glad to assist you in opening the IIF file.

This error will usually occur when the file association of the .iif file is changed to other applications other than MS Excel. You'll want to verify the type of file you are opening by right-clicking the file and choosing Properties. The file type is listed under Type of File.

If needed, you'll want to change the file association of the .iif file to open with MS Excel. This way, you'll be able to open the file.

You might want to read this article to learn how to import IIF files in QuickBooks Desktop: Export, import, and edit IIF files.

Please know you can continue to reach me here with any additional questions. Thanks for coming to the Community, wishing you continued success.