Are there any error messages?

Go to the Mozilla Add-ons Web Page {web Link} (There’s a lot of good stuff here) and search for a download manager.

This download manager works separately from the browser. The browser tells it what to download, and off it goes.

http://www.freedownloadmanager.org It is a powerful modern download accelerator and organizer for Windows and Mac.

Needless to say I had to use Chrome to download the file Freedownloadmanager. I would still like to know why Firefox can download some files and not others

Are there any error messages?

Have you tried using an add-on download manager?

No messages. Just "failed" in the download chevron. What download add on do you suggest

Sorry, I use a Legacy Firefox version and Legacy add-ons.

Start Firefox using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?

Start your Computer in safe mode with network support. Then start Firefox. Try Secure websites. Is the problem still there?

Starting Any Computer In Safe Mode (web link) Free Online Encyclopedia

https://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/

https://www.digitalcitizen.life/4-ways-boot-safe-mode-windows-10/ +++++++++++++++++++++++++++++++++++++++++++++++ If the problem goes away with the computer in Safe Mode, the problem is with one of the other programs on the system.

As a test, disable your protection programs.

It seems to be *.exe that wont download. No problems with PDF, CSV or QIF

Issue does not exist in safe mode. How does one find out which program is casing the situation?

The way to test add-ons is to disable them all, then re-enable them individually or in batches until you get a failure.

The only addons or extensions are one from Mozilla and one from Google. Disabling them made no difference

Then possibly it's something else in the profile.

Use these links to create a new profile. Use this new profile as is. Is the problem still there?

https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing-inaccessible

http://kb.mozillazine.org/Profile_folder_-_Firefox#Navigating_to_the_profile_folder

https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

Type about:profiles<enter> in the address bar.

Appreciate your help but a new profile did not help

I called for more help.

It's weird. Only exe file are involved. No problems with Chrome or Edge

Troubleshoot mode only gets you so far. Add-ons aren't the only possible cause of an issue. https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode

BY disabling download accelerator in Settings>general the problem has gone.

Performance Use recommended performance settings

           Learn more

These settings are tailored to your computer’s hardware and operating system.

           Use hardware acceleration when available

That was very good work. Well Done. Please flag your last post as Solved Problem as this can help others with similar problems. Go to that post and click the 'Solved' button to its right.

The problem has returned. The performance settings are disabled as per my note 12/10/21 8:25 pm

It's weird. Only exe file are involved.

Issue does not exist in safe mode. How does one find out which program is casing the situation?

Were you talking about the Computer in Safe Mode?

If the problem goes away with the computer in Safe Mode, the problem is with one of the other programs on the system.

As a test, disable your protection programs.

Disabling Symantec made no difference