HI, that version is not compatible to XP/Vista You are running the last release that is available for you being 52.9.0esr

• https://www.mozilla.org/en-US/firefox/organizations/all/#legacy

There will be no updates including security updates at months end.

Please move to a secure operating system for us all.

In https://addons.mozilla.org/firefox/ search using search term Video Downloader.

https://addons.mozilla.org/firefox/search/?platform=windows&q=Video%20downloader

Please make sure that you only download something that supports XP.

jmaclay said

I want to be able to download YouTubes onto a Windows 7 and need a Video Download helper but the add-on requires a Firefox version 57.0a1 which I don't seem to be able to down load. How can i do this or download YouTubes another way?

Ignore the a1 part of 57.0a1 as it is to say you need Firefox 57.0 or later Release to use these versions of that extension.

Hmm your useragent in More System Details in right of post is not quite right and you say you have Windows 7. Mozilla/5.0 (Windows NT 5.1; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0

The WOW64 means you have a 32-bit Firefox 52.9.0 ESR on 64-bit Windows. The NT 5.1 is for Windows XP so the WOW64 and NT 5.1 does not go together in normal useragent.

Firefox 61.0.2 run on Windows 7, 8, 10 however if your browser usergaent is showing as if you have Windows XP then you will get served 52.9.0 ESR when you download from www.mozilla.org or www.mozilla.org/firefox/all/

Perhaps you are running your web browsers in Windows XP compatibility mode. https://support.microsoft.com/help/15078/windows-make-older-programs-compatible

Perhaps you have modified your Firefox useragent https://support.mozilla.org/en-US/kb/how-reset-default-user-agent-firefox

Or maybe you enabled the privacy.resistFingerprinting in about:config so reset it to false.

edit: the Windows XP Professional x64 Edition can show WOW64 if using a 32-bit application. The 64-bit or Win64 Firefox requires 64-bit Windows 7, 8 (8.1), 10 to run as it will not run on 64-Vista and less common 64-bit XP. The vast majority of WinXP users that come here are using 32-bit Windows XP.

But anyways you mentioned onto a Windows 7 which is why the XP useragent does not seem right.

Pkshadow said

In https://addons.mozilla.org/firefox/ search using search term Video Downloader. https://addons.mozilla.org/firefox/search/?platform=windows&q=Video%20downloader Please make sure that you only download something that supports XP.

The https://addons.mozilla.org/en-US/firefox/addon/video-downloadhelper/ is an Extension and not a separate application so the OS being used is not really a concern as it works with desktop Firefox on Windows, Mac and Linux. Every version of this extension since Oct 2017 has required Firefox 57.0 or later.

Anyways this was on Windows 7 and not XP.

This is likely a problem with running Firefox in compatibility mode if you are on Windows 7 and aren't using a different computer to post this question.

Check that you do not run Firefox in compatibility mode. You can open the Properties of the Firefox desktop shortcut via the right-click context menu and check the "Compatibility" tab. Make sure that all items are deselected in the "Compatibility" tab of the Properties window.