Perhaps you are unaware of the changes made by version 98. I have pasted a link to the release notes. Firefox now generally downloads a file when you open it (both things happen). Are you getting the option to open a file if you right-click the link?

https://www.mozilla.org/firefox/98.0/releasenotes/

Hi Mark, it depends because servers are inconsistent in how they identify various types of files.

As the first step, could you try this: Open the Downloads list, right-click the CSV file that didn't follow instructions, and choose "Always Open Similar Files".

Firefox then should add a new entry to the Applications list for whatever content type that server indicated for the file. Most likely it will have a "Use Excel" action.

What if "Always Open Similar Files" is not available?

This usually indicates that the server provided Firefox a generic binary file content-type rather than one which is specific to CSV files. This is harder to work around. I have an add-on that can help. More info if needed.

terry21: I checked your referenced Release Notes link. Wow! what an absolutely terrible idea!! If I want to save file links, I'd prefer deciding to do so. In particular, I rarely save PDF files. Now, every file link I open will get automatically saved to my Downloads folder and completely clutter up that folder. Our office has a web app in which virtually every report has the ability to download a corresponding CSV or PDF file. 90% of the time, the user just looks at the opened document, but doesn't save it. Now we will have to periodically clean out our Downloads folders. I have one computer, not yet updated, with Desktop specified as the Downloads folder. I guess I'll have to change that. This behavior should be an option.

jscher2000: The CSV file type is in my Content Type / Action settings, so that's not the issue. Thanks for "Always Open Similar Files" tip. Also note that with your tip:

As the first step, could you try this: Open the Downloads list, right-click the CSV file that didn't follow instructions, and choose "Always Open Similar Files".

This has to be done via the downloads list that pops up at the upper-right of the window, as shown in Terry21's release notes link. Doing this from File > Open, then selecting the app and "Do this Automatically" does not work to actually open the file automatically when clicked on. I tried that all last evening to no avail. If done via the downloads list, then it does open automatically thereafter.

Behavior is still odd. If I check the setting "Always ask you where to save files", it does not ask and still downloads to the folder designated in "Save folders to". It this option now obsolete? Again, been experimenting with these settings all morning and not able to get prompted to save to some different folder.

More info ... OK, I see that the file type must be designated as "Always ask" in the Content Type/Action list in order to get prompted for a download location.

Hi Mark, someone should create a tree diagram of what does what. It sounds like you found it eventually.

Regarding File > Open, when Firefox opens a file from disk, it doesn't have as much information as when it gets a file from a web server because it doesn't have the content-type information. That could be one reason for inconsistent handling.