Hi phil1917, could you walk me through where this problem occurs. For example:

Here is the "all system and languages" download page:

https://www.mozilla.org/firefox/all/

Depending your browser's preferred language, it may redirect to U.S. English:

https://www.mozilla.org/en-US/firefox/all/

Then when you click the link for the download you want, the request will go to the download server. For example, for 64-bit Windows, U.S. English:

https://download.mozilla.org/?product=firefox-latest-ssl&os=win64&lang=en-US

Then that address will redirect to the setup file version for the "latest" which is Firefox 62.0.3:

https://download-installer.cdn.mozilla.net/pub/firefox/releases/62.0.3/win64/en-US/Firefox%20Setup%2062.0.3.exe

Can you indicate where the problem arises? For example, is it that last link which can't be reached (so the earlier one that redirects to it also doesn't work)?

No go. Did as you suggested. Still receive same message:

This site can’t be reached download-installer.cdn.mozilla.net’s server IP address could not be found. Try running Windows Network Diagnostics. DNS_PROBE_FINISHED_NXDOMAIN

Many thanks for trying. Phil

One more try (64-bit, U.S. English):

• http://ftp.mozilla.org/pub/firefox/releases/62.0.3/win64/en-US/
• http://archive.mozilla.org/pub/firefox/releases/62.0.3/win64/en-US/

If your system can't find those addresses, either, it seems suspicious to me.

phil1917 said

Try running Windows Network Diagnostics.

Try searching in the Windows search box for network diagnostics and see whether you can find that tool and run it.

Another to try is http://download-origin.cdn.mozilla.net/pub/firefox/releases/62.0.3/win64/

Able to get Firefox Icon on computer but could not open:

Your Firefox profile cannot be loaded. It may be missing or inaccessible.

Thanks everybody.

Hi phil1917, we have a different help article for that problem:

How to run Firefox when your profile is missing or inaccessible

Able to get Firefox but all bookmarks, etc are gone. Thanks.

Okay, let's try to find your data.

(1) Set Windows to show hidden files and folders:

https://support.microsoft.com/en-us/help/14201/windows-show-hidden-files

(2) Check for "orphaned" profile folders

Type or paste the following into the Windows Run dialog (Windows key + R) or the system search box and press Enter to launch Windows Explorer:

%APPDATA%\Mozilla\Firefox\Profiles

That should expand to:

C:\Users\your-user-name\AppData\Roaming\Mozilla\Firefox\Profiles

So here, one of the profile folders is going to be the one you just created (assuming you created a new profile). Are there any other folders here that might have your older data?

If not, check with your tech guy on whether he deleted any profile folders, or moved them to another location.

Did you had to create a new Firefox profile?

Weren't there older profiles present that you could use to restore personal data, either an "Old Firefox Data" folder on the desktop or an orphaned profile that wasn't registered in profiles.ini?

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

For recovering bookmarks you would need a backup from the bookmarkbackups folder.

• https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them

Problem solved. Many thanks to all.