If I click a link on a web page to download a file, Firefox offers me the option to "open with" a program or download to my downloads folder. I like having both options available but only one of them is working on the installation on one of my computers. If I choose the "open with" option, nothing happens. If I choose the download option, the file appears in my download folder and I can go there manually and open it.

When you select "Open with", Firefox generally saves the file in the Windows Temp folder, and passes the path over to the application you selected.

Is Firefox completing that first step of saving the file in the Temp folder? It would appear on the downloads list (click the arrow button on the toolbar) if it is.

I have tried adjusting the application associations and actions in settings. If I tell it to always "open with" for a file type, I still get the download option dialog when I download something.

Firefox usually will follow instructions, but users have noted a couple of exceptions over the years:

(1) The site sends a Content-Disposition: attachment (forced download) header. This triggers the download dialog in all cases.

(2) The site doesn't use the official Content-Type (MIME type) for a file but instead provides a generic type. This triggers the download dialog and the checkbox to do the same thing in the future is either missing, disabled, or doesn't work.

I have an add-on that can work around these issues. For #1, you need to choose from its menu:

• Click the Zzzz toolbar button to turn on the add-on
• Then click the button again and in the Content-Disposition Override section, check the box for Follow my settings (inline)

For #2, if a file has a .pdf or .docx extension, the add-on will fix the Content-Type automatically.

I have not tried a Refresh because it is not clear how this interacts with my Firefox online profile and I don't want to remove settings on the other computers that are working fine.

A Refresh wipes out a good amount of customization (Refresh Firefox - reset add-ons and settings), and only some of it would be synchronized back when you log in to your Firefox Account again. And there's a risk of wrong-way sync. So Refresh would be a last resort.

When you select "Open with", Firefox generally saves the file in the Windows Temp folder, and passes the path over to the application you selected. Is Firefox completing that first step of saving the file in the Temp folder? It would appear on the downloads list (click the arrow button on the toolbar) if it is.

It does appear in the downloads list but it is marked as "File moved or missing".

Looking a little deeper, I found I had an access control issue with my C:\Windows\Temp directory. Once I resolved that, the downloads started working.

Thanks for the background information and for confirming my suspicions about Refresh.

Looking a little deeper, I found I had an access control issue with my C:\Windows\Temp directory. Once I resolved that, the downloads started working.

Great! It's unfortunate that Firefox doesn't report those kinds of details on the drop-down.