Is there a reason why you executed a "refresh" of FF ?

Yes. Kaptcha stopped working and I could not get into YouTube, both problems resolved by the refresh.

thanks for the additional information.

i think it would be a good option for you is to install the password manager in windows, instead as a FF extension.

You see, FF already has a built in password manager. So its possible that installing an app that either competes or compliments what FF already has, could result in unexpected issues.

As for me, i have been using KeePass for many years. It's sill the old version and its in Windows. So it acts a little like a back up for my FF pw's. But the manager holds a lot more info that FF does not.

In any case, the point i am not making very well is that if you password manager is in windows instead of FF, then you wont putting your pws at risk in the event FF becomes corrupted.

Its the old "dont put all the eggs in one basket" ideology.

Now the new question is, why would FF not allow the password manager to install, to begin with? And if FF is going to stop all downloads?

I'm not sure. But maybe you might try invoking the older profiles and executing a un-install of that pw manager extension. Maybe having more than one copy is not allowed by the app?

To invoke the older profiles, go to the below to open the profile manager to see, launch other profiles on your FF system.

I hope the above makes sense. Let us know what you find.

Thank you for your suggestions. Keeper has been working perfectly as an add-on for a year and is vastly better than using Firefox for the purpose of remembering passwords. Something has changed. I am afraid you are on completely on the wrong tack here but thank you for trying to be helpful.

Just to clarify:

Download fails from the Mozilla Add-ons site at https://addons.mozilla.org/firefox/addon/keeper-password-manager-digita/ ?

Do other extensions install from the Add-ons site, or is there a more general problem?

Good suggestion. Yes they do.

One possible reason is that the redirect is blocked for one reason or another. What I mean is, the initial link for Keeper is:

https://addons.mozilla.org/firefox/downloads/file/3776100/keeper_password_manager_digital_vault-15.3.4-fx.xpi

But the server redirects that to a new address on a "CDN" server:

https://addons.cdn.mozilla.net/user-media/addons/581614/keeper_password_manager_digital_vault-15.3.4-fx.xpi?filehash=sha256:5b4825352c1041584b7c5c9540869282a8885f5d2f09ac970f7c41c5c844429e

From time to time, users report that their Firefox will not follow that redirect and therefore get the "connection failed" message, but I can't recall whether there is an explanation for it. Possibly some external filtering software?

(The way, to see this request chain, you need to open the Browser Console with Ctrl+Shift+J before clicking the Add to Firefox button, and add Requests to the filter at the right end of the filter bar. These requests do not show up in the tab-specific Network Monitor tool.)

Here's what I get on the browser console (attached)

Hmm, access denied deleting a file from the Windows Temp folder, unable to "unzip" the archive because it's corrupted, these are strange errors. What happens if you simply try to save the extension file to Downloads. Right-click the Add to Firefox button and use Save Link As to download it. Is that successful?

You can check the connection settings.

• Options/Preferences -> General -> Network: Connection -> Settings

If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly.

See "Firefox connection settings":

• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

Boot the computer in Windows Safe mode with network support to see if that has effect in case security software is causing problems.

• https://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• https://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

Sorry - no joy. I got 'this file is corrrupted'.

Tried changing Firefox newtork settings - didn't fix. On trying to enter safe mode I was asked for Recovery Key. This isn't supposed to happen. Bedtime here - will pick up tommorow. Thanks for your help.

I have a suspicion that some software doesn't want you to install this extension, but I don't know what software that would be.

Here's something else you could try as a temporary workaround. (I say temporary because this breaks normal updating.)

Can you find the Keeper extension in the pre-Refresh profile in the Old Firefox Data folder the Refresh feature created on your desktop?

Old Firefox Data\[profile.folder]\extensions\KeeperFFStoreExtension@KeeperSecurityInc.xpi

To cross-install that to your current profile, you can go to the built-in Add-ons page (Ctrl+Shift+A), click the "gear" button, then click Install Add-on from File... and point Firefox to the old file.

Thanks for your help - much appreciated. I don't want to waste any more time on this and will change to Edge, which has no problem with the Keeper download.