.CSV open in Excel with out having to go Security and Privacy

Once you have downloaded the Salesforce .csv, right-click on it and choose Open, not Open With... . You should get a warning that the file is from an unknown developer, and do you wish to ... and there is another Open button. Click that. It should display a brief progress bar that says verifying, and then it will open in Numbers, your default spreadsheet.

Quit Numbers. Single-click the .csv and press option+command+i to open the inspector mid-screen. In the Open with section, change Numbers to Excel, and click through the Change All... button.

You will likely have to perform the first paragraph ritual with future downloaded .csv files from that site, but they will then open in Excel and not Numbers. It may also be that these are Excel .csv that have a Byte Order Mark (BOM) at the beginning of the file, and Gatekeeper is treating it as an application-like, magic number because of the U+FEFF at the front of the document.

Do you want all .csv to be opened in Excel?

If so, Get Info on a .csv file and change the application associated with that file type to Excel.

I have no idea why you are getting a quarantine flag.

I also don't understand this:

Now I have to go to Security and Privacy and select in the Allow Apps Downloaded from: App Store and other Identified Developers.

Does that become unselected somehow? It should remain as you set it.

There was another user with the same problem here:

.csv Files default to Excel 2011, not Excel 2016

The OS, for whatever weird reason, is treating the .csv file as if it's an app. Which is of course, completely wrong. They're just text files.

We never did find a solution there, either. Even rebuilding the LaunchServices database didn't help.

Whatever the problem is, it's not widespread. I have no trouble saving or opening .csv files in Office 2016, no matter the source.

I have to do the above steps every time I open a .CSV even though I checked the always open with.

That check box only refers to that specific file, not all .csv files.

It is the file that is being quarantined. As I stated, I don't know why. It has nothing to do with Excel, identified or not.