To make Firefox open Quicken when download is complete, you need to go into Firefox Tools / Settings / General.Scroll down the page to Applications.Sort the list of supported file types by Content Type and scroll down to "Quicken OFX data" and set the Action to "Use Quicken Windows"
If you can't find this file type go to just past the bottom of the list of file types. Change "What should Firefox do with other files?" to "Ask ...". You'll get a prompt next time you download a QFX file.
Walter Baechelen said: The Chase bank download change would not load using Firefox. I had to go on Edge to make it work.