* type or paste '''about:support''' in the address bar and press Enter * (menu bar) Help > Troubleshooting Information * '3-bar' menu button > '?' Help > Troubleshooting Information type or paste about:support in the address bar and press Enter.(menu bar) Help > Troubleshooting Information.'3-bar' menu button > '?' Help > Troubleshooting Information.Since the file is tricky to edit, we usually suggest renaming the file and having Firefox rebuild it. Possibly the files that stores download handling preferences becomes corrupted. I'm puzzled why Firefox would just save a file without asking if it isn't specified in the visible list. Saving the file to my default location has not occurred since I completed this suggested process. I now had to click on the 'Save screen' in order for Firefox to present a File location window where I could select where I wanted the file to be saved. Pause while Firefox finishes its cleanup, then right-click handlers.json and Rename to something like handlersOLD.json. Leaving that window open, switch back to Firefox and Exit, either: This should launch a new window listing various files and folders in File Explorer. In the first table on the page, on the Profile Folder row, click the 'Open Folder' button. Open your current Firefox settings (AKA Firefox profile) folder using either 'Possibly the files that stores download handling preferences becomes corrupted. After review, I am certain that the procedure copied below resolved my problem (Profile corruption).

Firefox download option