Avast Security Browser Extension Not Available

[Riley7]

I did a clean install of Avast free several days ago. I installed the browser extension, but when asked to enable, I clicked later, or no. I was tired and did not want to be bothered at the moment.
So, now it is not available to enable except for in one browser.  How can I fix that?

[mchain]

Depends on what browser extension you've installed and what browser you want to run it in.

[Riley7]

It's the security browser extension. I would like it to run on IE 11, Firefox, and Chrome.

[Riley7]

I have uninstalled the extension & rebooted, installed & rebooted.  Still dont see it in available extensions.

Do I really have to do a clean install to fix this?

[mchain]

Avast Online Security is not automatically installed in the latest version of Firefox, 57.0.  Security features have been introduced in Firefox that block installation; you've need to allow or approve the install of AOS before it can install in your browser.  I do not have Chrome installed but would suspect this same process is in effect with Chrome also.

https://support.avast.com/en-us/article/Use-Online-Security