Question: Just curious, but why install a 3rd party app to provide a service that's already built into the browser? You're having issues with their app, but you have not shown us anything. What OS? What version of Firefox?

Sorry about that.

I have a McAfee subscription until September 2025 and I use it on my laptop 64-bit on windows 11 without any problems.

My desktop has 64-bit windows 10.

I use the latest Firefox 133.0.3 (64-bit) on both versions!

I can't install it as a Firefox add-on on my desktop only.

I can't install it as a Firefox add-on on my desktop only.

What does that mean? Show us something, but this is something you will need to contact McAfee about because it's not Firefox issue that the add-on won't install.

I believe the current McAfee True Key extension has been blocked for violations of the Extension policies https://extensionworkshop.com/documentation/publish/add-on-policies/

Not the first time a McAfee extension got blocked as this old list shows https://blocked.cdn.mozilla.net/

The company said that there are problems with True Key with the FireFox browser (although my Windows 11 laptop works perfectly with FireFox) and they are working on a solution.

So on my desktop computer switched to Chrome, which works perfectly with TK, just like with FireFox on my laptop.

Maybe I'll switch to Chrome on the laptop and it will be unified since the TK account works fine.

I think the topic is over! Thanks for all the replies.