I would suspect a temporary problem on the server. The DLL should send Firefox an HTML page -- indicated as such -- and you shouldn't get a download dialog. I'm not sure support volunteers would be able to test the site if it only happens after you log in, so you might mention it to the site.

Thanks. I'll try it again today. However, to clarify - I'm unable to log in via FF because when the 'sign in' button is clicked the only next action is for the dll to be downloaded. Can sign in as expected with other browsers

Just tried it, same result with FF, see attached screenshot

Hi brett611, thank you for the screenshot. It doesn't look like you have any downloader extensions that would modify how website responses are handled. Perhaps there is some setting I'm not thinking of.

Could you check whether your Firefox can open the page with clean settings:

New Profile Test

This takes about 3 minutes, plus the time to test your problem site(s).

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

Click the "Create a New Profile" button, then click Next. Assign a name like July2019, ignore the option to relocate the profile folder, and click the Finish button.

After creating the profile, scroll down to it and click the Launch profile in new browser button.

Firefox should open a new window that looks like a brand new, uncustomized installation. (Your existing Firefox window(s) should not be affected.) Please ignore any tabs enticing you to connect to a Sync account or to activate extensions found on your system so we can get a clean test.

Does the login form work any better in the new profile?

When you are done with the experiment, you can close the extra window without affecting your regular Firefox profile. (July2019 will remain available for future testing.)

THANKS!

With the new profile, it worked perfectly. I use a FF account to sync across work and home pc. I have no problem deleting things and starting over, just not sure how far I need to go to fix this. The default-release profile is in use and can't be deleted...how do purge that and use the profile I just created as the default?

Thanks again!!

Hi brett611, it's possible the test profile is already the new default profile. If you close all your Firefox windows and start Firefox again, which profile does it choose to start up in?

Please don't delete the old profile. There may be data in there that you realize you need after a couple of days or weeks and there's no backup (unless you make regular backups).

This article describes what the data and settings files in each profile hold. However, I suggest copying a couple files at a time so you can test whether they brought over a problem.

Recovering important data from an old profile

Thanks, you're right it is the default now. I deleted everything to be safe as I'm ok with losing bookmarks. Nothing else matters as I don't use FF for pswrds, addresses, etc

have a great one!

There would normally GET be appended to the link (?xxx) to request a specific (ad) file. In your case this GET data seems to be missing causing the download dialog to appear. This is likely done by some content blocking extension (you have UBO) or external application.